Bearing assembly with preload

Abstract

A wheel bearing assembly for a vehicle includes at least one rolling-element bearing having a first bearing ring and a second bearing ring defining therebetween a bearing interior, rolling elements disposed in the interior, and a seal assembly for sealing the bearing assembly. The seal assembly includes a sleeve-shaped element connected to the second bearing ring such that the sleeve-shaped element rotates with the second bearing, and the sleeve-shaped element includes a flange that forms an axial stop for the rolling elements. A carrier element is connected to the first bearing ring such the carrier element rotates with the first bearing ring, and the carrier element includes a radially extending annular flange. The radially extending annular flange supports a radially encircling seal having at least one seal lip, and the seal lip extends toward the second bearing ring and sealingly abuts on the sleeve shaped element.

Claims

1. A wheel bearing assembly for a vehicle comprising: at least one rolling-element bearing having a first bearing ring and a second bearing ring defining therebetween a bearing interior; rolling elements disposed in the interior; and a seal assembly for sealing the bearing assembly, wherein the seal assembly comprises a sleeve-shaped element connected to the second bearing ring such that the sleeve-shaped element rotates with the second bearing, the sleeve-shaped element comprising a flange that forms an axial stop for the rolling elements, and a carrier element connected to the first bearing ring such the carrier element rotates with the first bearing ring, the carrier element including a radially extending annular flange, wherein the radially extending annular flange supports a radially encircling seal having at least one seal lip, the seal lip extending toward the second bearing ring and sealingly abutting on the sleeve shaped element.

2. The wheel bearing assembly according to claim 1, wherein the at least one rolling-element bearing comprises first and second rolling element bearings.

3. The wheel bearing assembly according to claim 2, wherein the sleeve-shaped element is axially adjustable relative to the second bearing ring.

4. The wheel bearing assembly according to claim 2, wherein the sleeve-shaped element is press-fit on the second bearing ring and is displaceable relative to the second bearing ring by overcoming a friction of the press fit.

5. The wheel bearing assembly according to claim 4, wherein the first and second rolling-element bearings are preloadable in an axial direction by relatively displacing the first bearing rings and/or the second rings.

6. The wheel bearing assembly according to claim 2, wherein the second bearing ring comprises an inner bearing ring.

7. The wheel bearing assembly according to claim 2, wherein the sleeve-shaped element is disposed on a component receiving or supporting the rolling-element bearing.

8. The wheel bearing assembly according to claim 2, wherein the second bearing ring includes a cylindrical seat onto which the sleeve-shaped element is pushable-on under press-fit.

9. The wheel bearing assembly according to claim 2, wherein the sleeve-shaped element is axially fixed in a non-adjustable manner on the second bearing ring.

10. The wheel bearing assembly according to claim 9, wherein the sleeve-shaped element is connected to the second bearing ring in an interference-fit or materially-bonded manner.

11. The wheel bearing assembly according to claim 9, wherein the second bearing ring includes a circumferential groove into which the sleeve-shaped element is deformed.

12. The wheel bearing assembly according to claim 11, wherein the sleeve-shaped element forming the flange is inductively hardened at an axial end region facing the rolling elements.

13. The wheel bearing assembly according to claim 2, wherein the sleeve-shaped element includes a wear-resistant coating on a surface on an axial end region facing the rolling elements and/or on a region contacting the at least one seal lip.

14. The wheel bearing assembly according to claim 2, wherein the at least one seal lip comprises a first seal lip and a second seal lip and wherein the first seal lip sealingly abuts on the annular flange.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic sectional view through a first exemplary embodiment of the disclosed bearing assembly; and

[0034] FIG. 2 is a detail view of the bearing assembly depicted in FIG. 1.

DETAILED DESCRIPTION

[0035] In the following, identical or functionally equivalent elements are designated by the same reference numbers.

[0036] In FIG. 1 a bearing assembly 1 is depicted that includes two tapered roller bearings 2 and 3. The two tapered roller bearings 2, 3 each have an inner ring 4 or 5, but a common outer ring 6, or as depicted in FIG. 2 each have their own outer ring 6, 7. Rolling elements 8 or 9 are disposed between the bearing rings. Such bearing assemblies can be found in particular in wheel bearing units, wherein the bearing assemblies are fitted in a wheel hub R.

[0037] The bearing assembly depicted is embodied in a back-to-back arrangement. Flanges 10 and 11 on the inner rings 4, 5 limit the movability of the tapered rollers 8, 9 in the axial direction.

[0038] Here the flanges 10, 11 are configured as sleeve-shaped elements (flange sleeves), that are pushed-on onto the bearing rings 4, 5. While the sleeve-shaped element 11 of the inner ring 5 is fixed on the inner ring 5 as a fixed flange, this does not apply for the sleeve-shaped element 10 that forms the flange 10 on the inner ring 4. This sleeve-shaped element is embodied as an axially adjustable flange 10, i.e., it can also be adjusted in the axial direction on the inner ring 4 after the assembly of bearing rings and rolling elements.

[0039] Furthermore, it can be seen from FIG. 1 that the flange sleeves 10, 11 are simultaneously configured as contact sleeves for seal assemblies 12, 13. The seal assemblies 12, 13 are configured as cassette seals and include, as can also be seen in particular in the enlarged depiction from FIG. 2, an axially extending ring arm 14 and a radially extending annular flange 15. Furthermore, a seal lip 16 is attached on the radially extending flange 15, which seal lip 16 extends away from the axially extending ring arm 14 towards bearing inner ring 4, 5 and sealingly abuts on the flange sleeves 10, 11. Here the seal lip 16 can also be configured as a multi-part seal lip 16, which abuts with a first section 16-A on an axially extending section 10-A, 11-A of the flange sleeve 10, 11, and a second section 16-B on the section 10-B, 11-B of the flange sleeve 10, 11, which section 10-B, 11-B forms the flange.

[0040] Furthermore, FIG. 2 shows in particular that the flange sleeves 10, 11 are configured with press-fit to the inner ring 4. Here it is advantageous in particular if, as FIGS. 1 and 2 show, the inner ring 4 includes a cylindrical shoulder 18 on which the flange sleeve 10 is pushed-on under press-fit. Here during the assembly the sleeve-shaped element 11 forming the fixed flange is first pushed-on on the inner ring 5 under press-fit and fixed. This fixing can be effected via welding, in particular laser welding; however it is also possible to provide a groove 20 in the bearing inner rings 4, 5, into which groove 20 the flange sleeves 10, 11 are rolled up. It is also possible to deform the flange sleeves 10, 11 by hammer blows such that a clamping in the groove 20 occurs. In contrast, during installation, the sleeve-shaped element forming the axially adjustable flange 10 is axially displaced against the resistance of a friction between flange sleeve 10 and bearing ring 4 so that a predetermined preload can be generated in the bearing assembly.

[0041] The displacing of the sleeve-shaped element 10 forming the adjustable flange occurs here advantageously during the tightening of a shaft nut 22, via which the inner rings 4 and 5 are fixed against each other. During the tightening of the shaft nut 22, the rolling elements 8, 9 are pressed-on on the outer ring 6 via the inner rings 4, 5. Since the press-fit of the flange sleeve 10 is usually less than the force with which the shaft nut 22 displaces the inner rings 4, 5 into their end position, i.e., abutting each other, the flange sleeve 10 is displaced axially outward along the cylindrical shoulder 18. However, this displacing only occurs after overcoming of the counterforce generated by the friction, so that a preload is generated that is on the scale of the friction force. A predetermined preload can thereby be defined and determined.

[0042] At the same time the two preloads, namely the preload of the bearing assembly corresponding to the preload circuit V1 and the preload or clamping of the inner rings 4, 5 corresponding to the preload circuit V2 are separated from each other via the advancing of the shaft nut 22, so that even with a later inexact installation of the inner rings 4, 5 with respect to each other the predefined preload in the tapered roller bearing 1 itself remains.

[0043] If after advancing the shaft nut 22 the flange sleeve 10 is positioned in its end position on the cylindrical bearing seat 18, the position of the flange sleeve 10 can be fixed, for example, using an interference fit or material bonding. It is thereby ensured that even in operation a further axial displacing or loosening of the flange sleeve 10 does not occur. For this purpose, as with the fixed flange sleeve 11 on the inner ring 4 a groove 20 can be incorporated that preferably extends circumferentially about the bearing ring 4. After achieving of the predetermined preload the flange sleeve 10 can then be rolled up into the groove 20 or deformed, for example, by hammer blows, such that a clamping of the flange sleeve 10 in the groove 20 occurs. Alternatively it is of course also possible to attach the flange sleeve 10 on the inner ring 4 in a materially-bonded manner, for example, by welding, in particular laser welding. The forming of the groove 20 can then be omitted.

[0044] In order to keep the wear on the flange sleeve 10, 11 as low as possible it is furthermore provided that the axial flange section 10-B, 11-B of the flange sleeve 10-11, which flange section 10-B, 11-B faces the rolling elements 8, is induction-hardened. In contrast, an axial end region 10-C, 11-C (see FIG. 2) that faces away from the rolling elements 8 is not hardened. The not-hardened region 10-C, 11-C of the flange sleeve 10, 11 can thereby be plastically deformed so that a deforming of material into the groove 20 is possible. It is also possible to harden the region 10-A, 11-A on which the seal lips 16-A, 16-B run. The wear in this region can thereby be reduced.

[0045] Alternatively or additionally it is possible to provide the axial flange section 10-B, 11-B facing the rolling elements 8 and/or the region 10-A, 11-B of the flange sleeves 10-11, which region 10-A, 11-B faces the seal lips, with a wear-resistant coating. Due to this coating particularly with long operating times premature signs of wear in a contact region between the flange sleeves 10, 11 and the rolling elements 8 or the seal lips 16-A, 16-B can be avoided.

[0046] Instead of disposing the flange sleeves 10, 11 on the inner ring 4, as is depicted in FIGS. 1 and 2, it is of course also possible to place the flange sleeves 10, 11 on the outer ring 6 or on a bearing housing R comprising the outer ring.

[0047] As already mentioned above the disclosed bearing assemblies are of advantage in particular in wheel bearing units wherein the tapered roller bearings are installed under a predetermined preload. Simultaneously the inner rings 4 and 5 must usually generally be brought into a tightly abutting position in order to dispose a clip ring 24 (see FIG. 1) between them and axially secure the two inner rings 4 and 5 with respect to each other in operation. In particular in the solutions with location rings known from the prior art this has led to the problem that in the assembly precisely defined positions of the shaft nut are necessary in order to generate a defined preload. However, since this is very complicated in terms of assembly, to date a predetermined preload has usually been omitted.

[0048] If the tapered roller bearings are also to be sealed against an external environment, it has been shown that the use of standardized cassette seals with axially adjustable flanges was often not to be realized. In particular in solutions with axially adjustable flange sleeves the seals must be specially manufactured. Due to the above-described use of the flange sleeve as seal-lip contact and rolling-element support a standardized solution can thus be provided that can also be used with axially adjustable flange sleeves. However, sealed bearings with fixed flange sleeves can also be equipped with flange sleeves, which are simultaneously configured as contact sleeves for the seal lips of the seal assembly. If the seals are not introduced as a complete assembly set, it can be advantageous to design the seal carrier such that the axial ring section is disposed on the bearing inner side and the radial flange section is disposed on the bearing outer side. The seal carrier can thereby be simply pushed-on into the bearing assembly and in particular onto the flange sleeve.

[0049] In addition to a wear-reducing coating or hardening, the service life of the seal assembly and thus of the bearing assembly can also be increased by the rotational speed of the seal lips on the flange sleeve being lower than with an abutment of the seal lips on a bearing inner ring with a flange configured in an integrated manner. The reason for this is that the outer diameter in a bearing inner ring with integrated flange corresponds to the bearing-ring thickness+the flange height. A diameter reduction due to the cylindrical shoulder 18 is omitted. However, the rotational speed of the seal lips also thereby decreases, which leads to the increased service life.

[0050] It is further noted that rolling-element bearings other than the tapered roller bearing depicted can also include a flange sleeve that simultaneously serves as contact sleeve for the seal lips of a seal assembly.

[0051] Overall with the above-described bearing assembly a sealed bearing assembly can be provided that synergistically uses one element whereby on the one hand costs are saved and on the other hand installation steps can be simplified. At the same time with axially adjustable flanges using which a predetermined precise preload is achieved in the bearing a standardizable and easy-to-install solution for a seal is also provided.

[0052] Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved bearing assemblies.

[0053] Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

[0054] All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

[0055] 1 Bearing assembly [0056] 2 Rolling-element bearing [0057] 3 Rolling-element bearing [0058] 4 Inner ring [0059] 5 Inner ring [0060] 6 Outer ring [0061] 7 Outer ring [0062] 8 Rolling element [0063] 9 Rolling element [0064] 10 Adjustable flange sleeve [0065] 11 Fixed flange sleeve [0066] 12, 13 Seal assembly [0067] 14 Axial ring section [0068] 15 Radial flange [0069] 16 Seal lip [0070] 18 Cylindrical seat [0071] 20 Groove [0072] 22 Shaft nut [0073] 24 Clip ring [0074] V1 Preload circuit [0075] V2 Preload circuit [0076] R Hub