WO2008034417A2

WO2008034417A2 - Bearing unit for axial shaft positioning

Info

Publication number: WO2008034417A2
Application number: PCT/DE2007/001656
Authority: WO
Inventors: Jan Georgi; Arbogast Grunau
Original assignee: Schaeffler Kg
Priority date: 2006-09-22
Filing date: 2007-09-13
Publication date: 2008-03-27
Also published as: DE102006044903A1; WO2008034417A3

Abstract

The invention relates to a bearing unit for the axial positioning of a shaft (15), said unit comprising a roller bearing arrangement provided with at least one axial bearing (5), and an adjustment means which is coupled to the shaft (15) by an adjusting thread extending axially parallel to the shaft (15) such that an axial relative movement between the shaft (15) and the axial bearing (5) results from the rotation of the adjusting means. A shaft liner (17) is provided, for example, as the adjustment means, with a thread for adjusting the axial position of the shaft liner (17) and therefore the position of the shaft (15). Alternatively, on an axial bearing (5), an inner ring (13) can comprise an axial extension (25) with an inner thread which engages in an outer thread of the shaft (15). It is also possible to combine a spacer ring (16) arranged on the shaft side between the radial bearing (3) and the axial bearing (5) with an adjusting sleeve (33) comprising an outer thread. The shaft (15) can be positioned by the rotation of the outer ring (9). Variations on the adjustment principle are possible.

Description

Bearing unit for axial shaft positioning

description

Field of the invention

The invention relates to a bearing unit for axial shaft positioning with a roller bearing assembly.

To ensure trouble-free operation and to increase efficiency, it is necessary to axially adjust shafts or rotors as closely as possible to the surrounding structure, such as a gear or a housing. The axial end position can thereby, in particular when using shims, usually without additional installation or adjustment only realize a sufficiently accurate toleration of the individual components, but often brings a significant increase in costs.

In "The rolling bearing in the motor vehicle", FAG Kugelfischer Georg Schaefer & Co. Schweinfurt, Publication No. 05100 pp 182-185 a method for axial shaft positioning is described, which uses an angle bushing and is used in pinion shaft bearings the complete bearing set with shaft in one unit. To adjust the shaft, the entire unit is moved by means of calibrated shims. For shaft positioning, the entire unit must be removed. In cases where this is not feasible for design reasons, remove the bearings after measuring, insert the shims and then reinstall the bearings. This results in an increased installation costs.

520. ISBN3-78300290-7 pg 520 is concerned with shaft positioning in screw compressors. Screw compressors commonly use thrust bearings made of axial and radial bearings on the pressure side, especially with oil-free screw compressors The larger the gap, the greater the pressure losses and the lower the efficiency of the system, which is why very accurate shaft positioning is required, often using shims either on the shaft or in the shaft Axial shaft position adjustment is only possible by mounting and dismounting the bearings or by prior measurement and sorting of all relevant parameters such as housing tolerance, shaft tolerance and protrusion values on the bearing The greatest thicknesses are to stockpile.

Another known solution is described in "Rolling Bearing Technology", FAG Kugelfischer Georg Schaefer & Co. Schweinfurt, Publication No. DB 1976-1, pp. 18-19, in which the axial rotor adjustment takes place via a disc spring The disadvantage with the use of disc springs is that the adjustment only works in one direction when the nut of the thrust bearing presses against the disc spring case When loosening the nut, it may happen that the clamping force of the press fit is stronger than the axial force of the plate spring, so that the position of the shaft to the housing can not be changed.

DE 197 28 434 C2 includes a screw compressor, in which the axial shaft position similar to pinion shafts can be adjusted by an adjustable adjusting sleeve in the axial direction. The positioning of the Einstellbüchse by means of separate adjustment screws. The disadvantage here is that the arranged between housing and bearing Einstellbüchse engages strongly in the surrounding construction. Especially with screw compressors, however, it depends on a compact design, which is why a radially as close as possible arrangement of the rotors is sought.

In EP 1 517 054 A1, an external thread is integrated in the outer rings of tapered roller bearings for axial shaft adjustment. The axial positioning of the bearing via a corresponding thread in the housing. This is problematic in applications with radially exposed thrust bearing, for example in screw compressors. In this case, results between outer ring and housing a positive connection, which transmits forces in the axial and radial directions.

Furthermore, the use of thin-walled adjusting sleeves is known, which is plastically deformed during assembly over a defined axial preload and thereby defines the shaft end position. If the setting sleeve is set too tightly by mistake, loosening may cause the clamping force to be lost and the sleeve to be replaced.

The object of the present invention is therefore to provide a bearing unit which makes possible an accurate axial positioning of the shaft without requiring much installation effort, wherein complicated adjustment work is to be avoided. To solve this problem is generally a setting means which is coupled via an axially parallel to the shaft adjusting thread to the shaft, so that upon rotation of the adjusting an axial Relatiwerschie- bung between the shaft and thrust bearing results.

As preferred embodiments, several alternative storage units according to the appended claims 2, 6, 9, 12, 16, 19 are provided.

According to a first embodiment, a bearing unit according to the invention comprises a rolling bearing arrangement and a shaft bushing with a sliding seat arranged in its bore, a fitting located in the outer diameter for receiving the inner ring of at least one roller bearing and a thread for adjusting the axial position of the shaft bushing and thus the position of the shaft bushing Wave. The fit serves for centric insertion on a shaft seat. The thread of the shaft sleeve engages in a serving for receiving a shaft nut shaft thread.

The use of a shaft bushing requires only a small additional installation effort. The adjustment process can be carried out in a simple way.

The shaft bushing preferably has recesses in its end face, which can be designed, for example, as blind holes, grooves or the like. A tool can intervene in these recesses. In this way, the rotation of the shaft bushing is facilitated.

It is advantageous if the shaft bushing can be clamped axially. For this purpose, a shaft nut can be used. In this case, an adjustment of the previously set axial shaft position is avoided. In an advantageous embodiment, the inner rings located on the shaft bushing can be axially fixed on the shaft bushing. For fixing purposes, for example, a shaft nut or a forming ring is used.

In a modified embodiment, a bearing unit according to the invention comprises a rolling bearing arrangement with at least one axial bearing. The thrust bearing has on the inner ring an axial extension with internal thread, which engages in an external thread of the shaft. The thrust bearing is axially adjustable in the pushed onto the shaft seat state by rotation on the external thread of the shaft.

A major advantage of such an arrangement is that no additional components are needed because the adjustment function is integrated into the Axialla- ger.

Appropriately, an embodiment in which the extension over its inner circumference a radial groove and axially distributed over its end face has a plurality of recesses threaded. Screws for axial clamping of the inner ring on the shaft can be screwed into the recesses. In this embodiment can be dispensed with a shaft nut for axial clamping of the thrust bearing. The now more compact solution contributes to cost savings.

A further modified embodiment of the bearing unit according to the invention comprises a rolling bearing arrangement with at least one thrust bearing and at least one radial bearing, a spacer ring, which is arranged between radial bearings and thrust bearing shaft side, and an adjusting sleeve with external thread and two recesses for receiving two offset by 180 ° Mitnehmerstücken. The follower pieces are engaged with two opposed grooves of the outer ring of the thrust bearing. The shaft can be turned by turning the outer ring of the thrust bearing and the participants pieces associated rotation of the adjusting sleeve are positioned. Again, this solution requires only a small additional installation effort.

The adjusting sleeve may be provided according to an expedient embodiment with a plurality of radially distributed holes, which open into transverse bores. Through these holes lubricant can be introduced into the rolling bearing assembly. This makes it easy to lubricate the otherwise difficult to access bearings.

A bearing unit according to the invention comprises in another embodiment, a rolling bearing assembly having at least one radial bearing and at least one thrust bearing, the inner ring has an extension in the radial direction to the shaft, and an adjusting sleeve with internal thread and a circumferential nose, which is in engagement with the extension of the thrust bearing.

To realize this solution, only the inner ring of the thrust bearing must be provided with an extension and an additional adjustment sleeve can be mounted. The structural changes and the assembly costs are therefore limited.

Preferably, the shaft can be positioned by turning the adjusting sleeve. In an advantageous further developed embodiment, the adjusting sleeve can be clamped axially.

According to another expedient embodiment, the shaft can be positioned by rotation of an adjusting nut having radial grooves for engaging an adjusting tool in the adjusting sleeve. The axial tension of the adjusting sleeve with the adjusting nut takes place by turning the adjusting sleeve by means of adjusting tool. In this way, during the assembly process for the axial fixing of the outer rings in the housing, no additional chen auxiliary tools needed.

Finally, the specified object can be achieved by a bearing unit according to the invention, which has a rolling bearing arrangement with at least one radial bearing and at least one thrust bearing, the inner ring has a radial groove, and further with an adjusting nut with window-shaped recesses for receiving pressure segments, with the radial groove are engaged. The shaft can be positioned by turning the adjusting nut. The pressure segments should hereby sit axially almost free of play in the adjusting nut and in the radial groove of the inner ring of the thrust bearing. They thus ensure an axial play-free positioning of the thrust bearing on the shaft in both directions. The positive connection of inner ring, pressure segments and adjusting nut can not transmit moments. Therefore, turning the inner rings in the operating state can not cause any axial adjustment. As pressure segments preferably cylindrical rolling elements can be used. In an expedient embodiment, the adjusting nut is axially clamped.

A further modified bearing unit according to the invention comprises a rolling bearing arrangement with at least one thrust bearing and at least one radial bearing, the thrust bearing being exposed radially, and pitch profiles arranged on the end faces facing the respective other rolling bearing. The pitch profiles are rotatable radially to each other. The positioning of the shaft is done by twisting the pitch profiles towards each other. A major advantage of this solution is the space-saving accommodation of the additional function axial shaft adjustment, which can be less expensive integrated into existing structures. Various designs are possible in which the pitch profiles are located either on the end faces of the inner rings or the end faces of the outer rings. According to a further expedient embodiment, adjusting rings are arranged between the radial and thrust bearings, which are positively connected to the end faces facing the adjacent rolling bearing and in which the angled end faces facing the respective other rolling bearing are incorporated. Again, various designs are possible in which the adjusting rings are arranged either on the inner rings or on the outer rings. By using adjusting rings conventional rolling bearings can be used, which is not least in terms of cost is very beneficial.

Further advantages, details and developments of the present invention will become apparent from the following descriptions of preferred embodiments, with reference to the drawings. Show it:

1 shows a first design of a bearing unit according to the invention with an axially adjustable shaft bushing in a sectional view.

2 shows a second design of the bearing unit according to the invention with at least one thrust bearing, which is axially adjustable by rotation, in a sectional view;

FIG. 3 is a sectional view of a modified embodiment of the bearing unit shown in FIG. 2; FIG.

4 shows a third design of the bearing unit according to the invention with an adjusting sleeve with external thread, in a sectional view;

FIG. 5a shows the adjusting sleeve according to FIG. 4 in a cross-sectional view; FIG.

Fig. 5b is a sectional view taken along the line xx in Fig. 5a; 6 shows a fourth design of the bearing unit according to the invention with an adjusting sleeve with internal thread, in a sectional view;

FIG. 7 is a sectional view of a modified embodiment of the bearing unit shown in FIG. 6; FIG.

8 shows a fifth design of the bearing unit according to the invention with an adjusting nut with window-shaped recesses for receiving pressure segments, in a sectional representation;

9 shows a sixth design of the bearing unit according to the invention

Pitch profiles on rolling bearings, in a sectional view;

FIG. 10 is a partial sectional view of the bearing unit shown in FIG. 9; FIG.

11 is a view of the inner rings of the rolling bearing of the bearing unit of FIG .. 10

Fig. 1 shows a first construction of the storage unit according to the invention in a sectional view. In the housing 1, a radial bearing 3 and a thrust bearing 5 is arranged. The outer rings 7, 9 of the bearings are fixed in the housing. The inner rings 11, 13 receive the shaft 15. Between radial bearing 3 and thrust bearing 5 is a spacer ring 16, which ensures the maintenance of a minimum distance between the two camps. The bearings 3, 5 receive a shaft 15. On the shaft 15 there is a shaft bushing 17 with a sliding seat arranged in its bore and a fit located in the outside diameter. By means of fitting the shaft bushing 17 is inserted centrally on the shaft seat. On the outer fit of the inner ring 13 of the thrust bearing 5 is pushed. The shaft bushing 17 can also be dimensioned so that it also receives the inner ring of the radial bearing 11.

The shaft sleeve 17 is provided with a thread 19 which engages in a serving for receiving a shaft nut shaft thread. Depending on the direction of rotation of the shaft 15, the thread 19 of the shaft bushing 17 can be executed right or left handed. Preferably, a fine thread is used. Upon rotation of the shaft sleeve 17 results in a linear displacement of the shaft 15 via the thrust bearing 5 in the desired position. The axial bearing 5 is continuously adjusted by the rotation until the desired position is reached.

The rotation of the shaft bushing 17 is facilitated by the fact that recesses are provided in its front side, which allow by means of a suitable tool, the slight rotation of the shaft bushing 17 on the shaft 15. The recesses may be designed as blind holes, grooves or the like. The position of the shaft sleeve 17 is ensured by the fact that the sleeve is braced with a shaft nut 21. The thrust bearing 5 is clamped axially by means of sleeve nut 23 on the shaft bushing 17. Instead of the shaft nut 21 or sleeve nut 23 may also be another suitable support member may be used, for example, a forming ring raised.

Hg. 2 shows a second design of the storage unit according to the invention in a sectional view. In the housing 1, the radial bearing 3 and the thrust bearing 5 is arranged. The bearings 3, 5 take the shaft 15. The thrust bearing has on the inner ring 13 on an axial extension 25 with internal thread, which engages in an external thread of the shaft 15. For axial adjustment of the thrust bearing 5 this is rotated to the external thread of the shaft 15. Securing the axial shaft position can be done by countering by means of shaft nut 21. Rg. 3 shows a modified embodiment of the design shown in Rg. 2 in a sectional view. In this embodiment, the function of the shaft nut in the axial extension 25 of the thrust bearing 5 is integrated. The axial extension 25 has for this purpose over its inner circumference a radial groove and axially distributed over its end face a plurality of recesses threaded. In the recesses screws 27 can be screwed for axial clamping of the inner ring 13 on the shaft 15.

FIG. 4 shows a third design of the bearing unit according to the invention in a sectional view. In the housing 1, the radial bearing 3 and the thrust bearing 5 is arranged. The thrust bearing 5 may be, for example, a four-point bearing.

Between radial bearing 3 and thrust bearing 5 is the spacer ring 16. Die

Bearings 3, 5 receive the shaft 15. In the outer ring 9 of the thrust bearing 5, two opposing grooves are introduced. Between radial bearing 3 and thrust bearing 5 is an adjusting sleeve 33, which in a thread in the

Housing bore is screwed.

The adjusting sleeve 33 has an external thread and two recesses for receiving two offset by 180 ° Mitnehmerstücken 35. The Mitneh- merstücke 35 are engaged with the grooves of the outer ring 9 of the thrust bearing 5 in engagement. The positioning of the shaft 15 is effected by turning the outer ring 9 of the thrust bearing 5 and the rotation of the adjusting sleeve 33 connected thereto via the driving pieces 35. The adjusting sleeve 33 is preferably secured against further rotation via an adhesive connection. After the shaft positioning, the adjusting sleeve 33 can be clamped axially via the outer ring 9 of the axial bearing 5 by a plate spring. In this way it is additionally protected against twisting.

FIG. 5 shows the adjusting sleeve 33 in detail, in a cross-sectional view in FIG. 5a and in FIG. 5b in a sectional view along the line xx. The adjusting sleeve 33 can be provided with an additional lubricating function. For this purpose, a plurality of radially distributed holes 37, in transverse bores 39 open into the adjusting sleeve 33 introduced. Through these holes 37, 39 lubricant can be introduced into the rolling bearing assembly.

6 shows a fourth design of the bearing unit according to the invention in a sectional representation. In the housing 1, the radial bearing 3 and the thrust bearing 5 is arranged. The bearings 3, 5 take the shaft 15. The inner ring 13 of the thrust bearing 5 is provided with an extension 41 in the radial direction to the shaft 15. The bearing unit further comprises an adjusting sleeve 43 with internal thread, which has a circumferential nose 45. The nose 45 is engaged with the extension 41 of the thrust bearing 5 in engagement. The positioning of the shaft 15 is effected by turning the adjusting sleeve 43. To secure the setting, the adjusting sleeve 43 is axially clamped to the thrust bearing 5 by means of shaft nut 21.

Fig. 7 shows a modified embodiment of the bearing unit shown in Fig. 6 in a sectional view. The positioning of the shaft is realized here by rotation of an adjusting nut 45. The adjusting nut 45 is provided with radial grooves for engaging a setting tool in the adjusting sleeve 43. The axial clamping with the adjusting nut 45 is effected by turning the adjusting sleeve 43 by means of adjusting.

8 shows a fifth design of the bearing unit according to the invention in a sectional representation. In the housing 1, the radial bearing 3 and the thrust bearing 5 is arranged. The bearings 3, 5 take the shaft 15. The inner ring 13 of the thrust bearing 5 has a radial groove, in which exactly fitting pressure segments 47 engage. The pressure segments 47 are also in communication with an adjusting nut 45. The adjusting nut 45 is provided with window-shaped recesses for this purpose. Before the shaft assembly, the pressure segments 47 are inserted through the bore of the adjusting nut 45. The shaft can be positioned by turning the adjusting nut. For axial clamping in turn serves the shaft nut 21. As pressure segments 47, for example, cylindrical rolling elements can be used. 9 shows a sixth design of the bearing unit according to the invention in a sectional representation. In the housing 1, the radial bearing 3 and the thrust bearing 5 is arranged. The bearings 3, 5 take the shaft 15. The thrust bearing 5 is radially released. On the other rolling bearings facing end surfaces 49, 51 of the inner rings 11, 13 are pitch profiles. With the rotation of the inner rings 11, 13, the pitch profiles rotate radially to each other. In this case, the thrust bearing 5 is set axially on the shaft 15 and thus the shaft 15 is positioned axially to the surrounding structure. In order to simplify the axial displacement, the fit of the bore of the thrust bearing 5 is opened before the adjustment process. Securing the axial shaft position is done by countering by means of shaft nut 21st

To illustrate the arrangement of the pitch profiles on the end faces of the inner rings 11, 13, reference is made to FIGS. 10 and 11, in which the details are better recognizable.

In other embodiments, the pitch profiles can also be arranged on the respective opposite end faces of the outer rings 7, 9 of the bearings 3, 5. A particularly advantageous embodiment uses additional adjusting rings, in which the pitch profiles are incorporated. These adjustment rings can be used when using conventional bearings. The pitch profiles are in this case incorporated in the other rolling bearing facing faces of the Einstellringe. The adjacent rolling bearing facing faces of the adjusting rings are positively connected to the rolling bearing, either on the inner rings or on the outer rings. They are entrained when turning the inner and outer rings and thereby caused an axial displacement of the thrust bearing on the shaft and thus the positioning of the shaft.

This principle can also be used for adjusting the axial air, eg for pitched angular contact ball bearings or tapered roller bearings. LIST OF REFERENCE NUMBERS

1 housing

3 radial bearings

5 thrust bearings

7 outer ring of the radial bearing

9 outer ring of thrust bearing

11 inner ring of the radial bearing

13 Inner ring of thrust bearing

15 wave

16 spacer ring

17 shaft bush

19 Thread of the shaft bush

21 shaft nut

23 rifle nut

25 axial extension

27 screws

33 adjusting sleeve

35 entrainment pieces

37 radially distributed holes

39 cross holes

41 radial extension

43 Adjusting sleeve with internal thread

45 adjusting nut

47 pressure segments

49 end face of the radial bearing inner ring

51 end surface of the thrust bearing inner ring

Claims

claims

1. A bearing unit for the axial positioning of a shaft (15), comprising a rolling bearing arrangement with at least one thrust bearing (5), and an adjusting means which is coupled via an axially parallel to the shaft (15) extending adjusting thread to the shaft (15), so that upon rotation of the adjusting means an axial Relatiwerschiebung between the shaft (15) and thrust bearing (5) results.

2. Storage unit according to claim 1, comprising:

- The rolling bearing assembly (3, 5) and

- A shaft bushing (17) with a sliding seat arranged in its bore, an outer diameter fit to

Receiving the inner ring (13) of at least one rolling bearing (5), wherein the fit for centric placement on a shaft seat, and with a thread for adjusting the axial position of the shaft sleeve (17) and thus the position of the shaft (15), wherein the Thread of the shaft sleeve (19) engages in a for receiving a shaft nut (21) serving shaft thread.

3. Bearing unit according to claim 2, characterized in that the shaft bushing (17) has recesses in its end face.

4. Bearing unit according to claim 2 or 3, characterized in that the shaft bushing (17) is axially braced.

5. Bearing unit according to one of claims 2 to 4, characterized in that the or on the shaft bushing (17) located inner rings (13) are axially fixable on the shaft bushing.

6. Bearing unit according to claim 1, comprising the roller bearing assembly with the thrust bearing (5), which on the inner ring (13) has an axial extension (25) with internal thread, which engages in an external thread of the shaft (15), and wherein the thrust bearing (5 ) in the pushed onto the shaft seat state by rotation on the external thread of the shaft (15) is axially adjustable.

7. Bearing unit according to claim 6, characterized in that the extension (25) is axially braced.

8. Bearing unit according to claim 7, characterized in that the extension (25) has a radial groove distributed over its inner circumference and axially distributed over its end face a plurality of recesses, wherein in the recesses screws (27) for axial clamping of the inner nenring (13) on the shaft (15) are screwed.

9. Storage unit according to claim 1, comprising:

- The rolling bearing assembly with the thrust bearing (5) and at least one radial bearing (3);

- A spacer ring (16) which is arranged on the shaft side between the radial bearing (3) and thrust bearing (5); such as - An adjusting sleeve (33) with external thread and two recesses for receiving two offset by 180 ° Mitnehmerstücken (35), wherein the Mitnehmerstücke (35) with two opposite grooves of the outer ring (9) of the thrust bearing (5) are engaged, and wherein by turning the outer ring (9) of the thrust bearing and the over

Mitnehmerstücke (35) associated rotation of the adjusting sleeve (33), the shaft (15) is positionable.

10. Bearing unit according to claim 9, characterized in that the adjusting sleeve (33) via the outer ring (9) of the thrust bearing (5) is axially clamped.

11. Bearing unit according to claim 9 or 10, characterized in that the adjusting sleeve (33) has a plurality of radially distributed bores (37) which open into transverse bores (39) and which serve for introducing lubricant into the rolling bearing arrangement.

12. A storage unit according to claim 1, comprising:

- The rolling bearing assembly with the thrust bearing (5) and at least one radial bearing (3), wherein the inner ring (13) of the thrust bearing (5) has an extension in the radial direction to the shaft; and

- An adjusting sleeve (43) with internal thread and a circumferential nose, which is in engagement with the extension of the thrust bearing (5).

13. Bearing unit according to claim 12, characterized in that the shaft (15) by rotation of the adjusting sleeve (43) is positionable.

14. Bearing unit according to claim 13, characterized in that the adjusting sleeve (43) is axially clamped.

15. Bearing unit according to claim 12, characterized in that the shaft (15) by rotation of an adjusting nut (45) having radial grooves for engagement of a setting tool in the adjusting sleeve (43), is positionable, wherein an axial strain with the adjusting nut (15). 45) by turning the adjusting sleeve (43).

16. A storage unit according to claim 1, comprising:

- The rolling bearing assembly having at least one radial bearing (3) and the thrust bearing (5), the inner ring (13) has a radial groove; and - an adjusting nut (45) having window-shaped recesses for receiving pressure segments (47) engaging the radial groove, the shaft (15) being positionable by rotation of the adjusting nut (45).

17. Bearing unit according to claim 16, characterized in that the pressure segments (47) are cylindrical rolling bodies.

18. Bearing unit according to claim 16 or 17, characterized in that the adjusting nut (45) is axially clamped.

19. A storage unit according to claim 1, comprising:

- The rolling bearing assembly with the thrust bearing (5) and at least one radial bearing (3), wherein the thrust bearing (5) is radially free; and

- Gradient profiles on the other rolling bearing (3,5) facing end faces of the rolling bearing (5, 3), wherein the pitch profiles are radially rotatable relative to each other and the positioning of the shaft (15) by rotation of the pitch profiles to each other.

20. Bearing unit according to claim 19, characterized in that the pitch profiles are located on the end faces of the inner rings (11, 13) of the roller bearings.

21. Bearing unit according to claim 19, characterized in that the pitch profiles on the end faces of the outer rings (7, 9) are located.

22. Bearing unit according to claim 19, characterized in that between the radial and thrust bearings (3, 5) adjusting rings are arranged, which are positively connected to the adjacent rolling bearing end faces and in whose respective other rolling bearing facing end faces, the pitch profiles are incorporated.

23. Bearing unit according to claim 22, characterized in that the adjusting rings on the inner rings (11, 13) of the rolling bearing (3, 5) are arranged.

24. Bearing unit according to claim 22, characterized in that the adjusting rings on the outer rings (7, 9) of the rolling bearing (3, 5) are arranged.

25. Bearing unit according to one of claims 19 to 24, characterized in that the fit of the bore of the thrust bearing (5) can be opened.