BEARING ASSEMBLY

Abstract

A bearing assembly, preferably a wheel bearing assembly, includes at least one first ring and at least second ring, at least one of the first and second rings being rotatable and a bearing interior being defined between the first and second rings. The first ring(s) are designed to be attached with press fit to a component formed of a first material with a first coefficient of thermal expansion, the first ring (s) being formed of a second material with a second coefficient of thermal expansion different than, preferably lower than, the first coefficient of thermal expansion. At least one seal unit is provided to seal an axially outer side of the bearing assembly and includes a carrier element formed of a third material with a third coefficient of thermal expansion, the third coefficient of thermal expansion is at least as high as the first coefficient of thermal expansion.

Claims

1. A bearing assembly comprising: a component formed of a first material with a first coefficient of thermal expansion; at least one first ring adapted to be attached by a press fit to the component and formed of a second material with a second coefficient of thermal expansion, the second coefficient of friction being lower than the first coefficient of thermal expansion; at least one second ring defining a bearing interior with the first ring, at least one of the first ring and the second ring being rotatable relative to the other one of the first ring and the second ring; and at least one seal unit configured to seal an axially outer side of the bearing assembly and including a carrier element formed of a third material with a third coefficient of thermal expansion, wherein the third coefficient of thermal expansion is substantially at least as high as the first coefficient of thermal expansion.

2. The bearing assembly according to claim 1, wherein the carrier element is inserted with a press fit on the axially outer side of the bearing assembly.

3. The bearing assembly according to claim 1, wherein the seal unit includes at least one seal lip disposed on the carrier element and configured to seal the bearing interior.

4. The bearing assembly according to claim 1, wherein the carrier element includes at least one first leg extending axially and sealingly abutting against the at least one first ring.

5. The bearing assembly according to claim 4, wherein the carrier element includes at least one second leg extending radially from the first leg such that a gap is defined radially between the second leg and the at least one second ring.

6. The bearing assembly according to claim 5, wherein the second leg is integrally formed with the first leg.

7. The bearing assembly according to claim 5, wherein the second leg is formed as a separate clamping ring attached by a press fit to the first leg.

8. The bearing assembly according to claim 7, wherein the second leg is configured to attach the at least one seal lip to the carrier element and/or the second leg is formed from a fourth material with a fourth coefficient of thermal expansion, wherein the fourth coefficient of thermal expansion is substantially at least as high as the first coefficient of thermal expansion.

9. The bearing assembly according to claim 1, wherein the at least one seal unit further includes at least one flinger having an axially extending section sealingly abutting against the second ring and configured to form a slip surface for the at least one seal lip and at least one radially extending section configured to form a gap with the carrier element.

10. The bearing assembly according to claim 1, wherein the third coefficient of thermal expansion is substantially equal to the first coefficient of thermal expansion and/or the fourth coefficient of thermal expansion is substantially equal to the first coefficient of thermal expansion.

11. The bearing assembly according to claim 1, wherein the first material and the third material are identical to each other and/or the first material and the fourth material are identical to each other.

12. The bearing assembly according to claim 1, wherein the first material, the third material and the fourth material are each a light metal and the second material is steel.

13. The bearing assembly according to claim 1, wherein the component is a hub of a wheel bearing assembly.

14. A bearing assembly comprising: a component formed of a first material with a first coefficient of thermal expansion; at least one first bearing ring adapted to be attached by a press fit to the component and formed of a second material with a second coefficient of thermal expansion, the second coefficient of friction being lower than the first coefficient of thermal expansion; at least one second bearing ring disposed within or around the first bearing ring so as to define a bearing interior, at least one of the first ring and the second ring being rotatable relative to the other one of the first ring and the second ring about a rotational axis; and at least one seal unit configured to seal an axially outer side of the bearing assembly and including a carrier element press fit to the first bearing ring such that a portion of the first bearing ring is disposed between the carrier element and the component, the carrier element being formed of a third material with a third coefficient of thermal expansion and the third coefficient of thermal expansion is substantially at least as high as the first coefficient of thermal expansion.

15. The bearing assembly according to claim 14, wherein the carrier element is configured to retain the first bearing ring coupled with the component at high operating temperatures.

16. The bearing assembly according to claim 14, wherein the carrier element includes an axially-extending first leg press fit to the first bearing ring and at least one second leg extending radially from the first leg such that an annular gap is defined radially between the second leg and the at least one second bearing ring.

17. The bearing assembly according to claim 16, wherein the second leg is integrally formed with the first leg or is formed as a separate ring attached to the first leg by a press fit and formed of a fourth material with a fourth coefficient of thermal expansion at least as high as the first coefficient of thermal expansion.

18. The bearing assembly according to claim 14, wherein the seal unit includes at least one seal lip disposed on the carrier element and configured to seal the bearing interior.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] In the following the invention is described in more detail using the exemplary embodiments depicted in the drawings. Here the exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the pending claims.

[0022] FIG. 1 shows a schematic sectional view through a bearing assembly according to a first embodiment,

[0023] FIG. 2 shows a schematic sectional view through a bearing assembly according to a second embodiment,

[0024] FIG. 3 shows a schematic sectional view through a bearing assembly according to a third embodiment,

[0025] FIG. 4 shows a schematic sectional view through a bearing assembly according to a fourth embodiment, and

[0026] FIG. 5 shows a schematic sectional view through a bearing assembly according to a fifth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0027] In the following, identical or functionally equivalent elements are designated by the same reference numbers. FIG. 1 shows a bearing assembly 1, in particular a wheel bearing assembly, that can be used in motor vehicles, such as, for example, a truck. The bearing assembly 1 comprises a hub 2 that is formed from a first material with a first coefficient of thermal expansion. For example, the hub 2 can be formed from a light metal, such as for example, aluminum, an aluminum alloy, a magnesium alloy, etc. The hub 2 includes a plurality of attachment openings (not shown), via which it is connectable to a wheel (not shown).

[0028] Furthermore, the bearing assembly 1 comprises a first ring 8 and a second ring 6, wherein the first ring 8 and the second ring 6 are rotatable relative to each other about a rotational axis 10 and define a bearing interior 12 between them. In FIG. 1, the first ring 8 is a two-part ring and includes a first part 8-1 and a second part 8-2. Alternatively, the first ring 8 could also be a one-part ring. Furthermore, in FIG. 1, the first ring 8 is a rotating ring and the second ring 6 is a stationary ring, although alternatively, the first ring 8 may be a stationary ring and the second ring 6 may be a rotating ring. The first ring 8 is designed to be attached in the hub 2 with press fit. Furthermore, the first ring 8 is formed from a second material with a second coefficient of thermal expansion that is different from the first coefficient of thermal expansion. In particular, the first coefficient of thermal expansion is higher than the second coefficient of thermal expansion. For example, the first ring 8 is manufactured from a bearing steel.

[0029] In FIG. 1, the bearing assembly 1 is a rolling-element bearing assembly that includes a first row of rolling elements 4 and a second row of rolling elements 4. The rolling elements 4 may be tapered rollers, cylindrical rollers, balls, needles and/or any other known type of rolling elements, each one of the first and second rows including the same type or different types of rolling elements 4. Alternatively, the bearing assembly 1 can also include only a single row of rolling elements.

[0030] In order to reliably protect the bearing interior 12 of the bearing assembly 1 from external contaminants, such as, for example, dust, dirt, water, and other particles, the bearing assembly 1 includes a seal unit 14 that seals the bearing assembly 1 on an axially outer side. The seal unit 14 includes a carrier element 16 and at least one seal lip 18. For example, the seal unit 14 can include two or more seal lips 18, FIG. 1 showing a seal unit 14 that includes two seal lips 18. The seal lip(s) 18 can be attached to the carrier element 16, for example, by adhesive bonding, vulcanization, and/or clamping.

[0031] At the same time, in order to reliably secure the first ring 8 in the hub 2 over the entire operating temperature range by a press fit, the seal unit 14 includes a carrier element 16 that is formed from a third material with a third coefficient of thermal expansion, wherein the third coefficient of thermal expansion is substantially at least as high as the first coefficient of thermal expansion. In FIG. 1, the carrier element 16 is also manufactured from light metal, preferably from the same light metal as the hub 2. Of course, the bearing assembly 1 can also include more than one seal unit 14. For example, the bearing assembly 1 can be provided with a seal unit 14 on each one of the two axially outer sides or ends.

[0032] Since the carrier element 16 has a coefficient of thermal expansion that is substantially at least as high as the coefficient of thermal expansion of the hub 2, the carrier element 16 expands together with the hub 2 at high operating temperatures, or contracts with the hub 2 at low operating temperatures. That is, at high operating temperatures, the carrier element 16 expands to a greater degree than the first ring 8, with the result that the carrier element 16 deforms the first ring 8. A secure fit of the bearing assembly 1 in the hub 2 can thus be ensured, even when, due to the high operating temperature, the hub 2 expands to a greater degree than the first ring 8. In the case of a low operating temperature, the carrier element 16 contracts together with the hub 2, with the result that the deformation of the first ring 8 decreases with decreasing temperatures. As a result, a failure of the hub 2 and/or a jamming or disrupting of the bearing function of the bearing assembly 1 is avoided.

[0033] In FIG. 1, the carrier element 16 is inserted with a press fit on the axially outer side of the bearing assembly 1 to secure the seal unit 14 in the bearing assembly 1, and is in sealing contact with the first ring 8. As can be seen in FIG. 1, the carrier element 16 is preferably disposed on a shoulder 21 of the first ring 8, and most preferably press fit to the first ring 8 such that a portion of the ring 8 is disposed between the carrier element 16 and the component 2. In particular, the first ring 8 has a reduced material thickness in the region of the shoulder 21 in the radial direction so that in the case of an expansion due to operating temperature changes, the first ring 8 can be more easily deformed in this region by the carrier element 16.

[0034] FIGS. 2 and 3 each show a bearing assembly 1 according to a second embodiment and third embodiment, respectively. The bearing assemblies 1 of FIG. 2 and of FIG. 3 differ from the bearing assembly 1 of FIG. 1 in that the seal unit 14 further includes a flinger 20. The flinger 20 has an axially extending section 22 and a radially extending section 24, wherein the axially extending section 22 abuts against the second ring 6. Furthermore, the axially extending section 22 and/or the radially extending section 24 is configured to form a slip surface for the seal lips 18 of the seal unit 14.

[0035] Both in the embodiment shown in FIG. 2 and in the embodiment shown in FIG. 3, the radially extending section 24 is configured to form an annular gap or a gap seal with the carrier element 16. This gap further reduces the risk of external contaminants, such as dust, dirt, and other particles, reaching and damaging the at least one seal lip 18 and/or penetrating into the bearing interior 12.

[0036] In FIG. 2, the radial section 24 extends in the radial direction to an extent that an annular gap 25 is formed between a radial end of the radial section 24 and the carrier element 16. In this case, the axial end surface of the radial section 24 and the axial end of the carrier element 16 can be oriented in alignment with each other. In FIG. 3, the radial section 24 extends axially outside the axial end surface of the carrier element 16, such that in this region, the carrier element 16 and the radial section 24 at least partially axially oppose each other and form a gap. This further reduces the risk of external contaminants penetrating into the bearing interior 12.

[0037] FIG. 4 shows a bearing assembly 1 according to a fourth embodiment. The bearing assembly 1 of FIG. 4 differs from the bearing assembly 1 of FIG. 1 in that the carrier element 16 includes a first leg 26 that extends axially and a second leg 28 that extends radially from the first leg 26 and is formed one-piece or integral with the first leg 26. Preferably, the second leg 28 extends in the radial direction to the extent that an annular gap 30 is formed between the radial end of the second leg 28 and the second ring 6. This further reduces the risk of external contaminants, such as dust, dirt, and other particles, reaching and damaging the at least one seal lip 18 and/or penetrating into the bearing interior 12.

[0038] FIG. 5 shows a bearing assembly 1 according to a fifth embodiment. The bearing assembly 1 of FIG. 5 differs from the bearing assembly 1 of FIG. 4 in that the second leg 28 is formed as a separate clamping ring that is attached to the first leg 26 by a press fit. In addition, the second leg 28 formed as clamping ring can advantageously be formed to attach the at least one seal lip 18 to the carrier element 16. The second leg 28 formed as clamping ring can be formed from the same material as the carrier element 16. Alternatively, the second leg 28 formed as a clamping ring can be formed from a fourth material with a fourth coefficient of thermal expansion, wherein the fourth coefficient of thermal expansion is substantially at least as high as the first coefficient of thermal expansion.

[0039] In summary, by providing the seal unit 14 that includes a carrier element 16 that is formed from a material that has a coefficient of thermal expansion that is substantially at least as high as the coefficient of thermal expansion of the hub 2, a relative rotation of the pressed-in ring 8 in the hub 2 can be prevented in the high operating temperature range. In addition, this also makes it possible to be able to reduce the critically high circumferential stresses in the hub 2 in the low operating temperature range so far that they remain significantly below the permissible material limit.

[0040] 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.

[0041] 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.

[0042] 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. The invention is not restricted to the above-described embodiments, and may be varied within the scope of the following claims.

REFERENCE NUMBER LIST

[0043] 1 Bearing assembly [0044] 2 Hub [0045] 4 Rolling element [0046] 6 Second ring [0047] 8 First ring [0048] 10 Rotational axis [0049] 12 Bearing interior [0050] 14 Seal unit [0051] 16 Carrier element [0052] 18 Seal lips [0053] 20 Flinger [0054] 21 Shoulder [0055] 22 Axial section [0056] 24 Radial section [0057] 25 Gap [0058] 26 First leg [0059] 28 Second leg [0060] 30 Gap