Wheel bearing unit, in particular for a motor vehicle

Abstract

The invention relates to a wheel bearing unit (10), in particular for a motor vehicle, having an outer ring (2) and an inner ring, which is fixed on a wheel hub (3), wherein a seal device (1) is provided between the outer ring (2) and the wheel hub (3), wherein the seal device (1) comprises at least one sealing element (4) and one plate element (5), wherein the sealing element (4) is fastened to the outer ring (2) and the plate element (5) is fastened to the wheel hub (3), wherein the plate element (5) has an axial part (5a) and a radial part (5b), wherein, on the axial part (5a), the plate element (5) is fully provided with a coating (6) on the surface facing the wheel hub (3), and wherein the plate element (5) is connected to the wheel hub (3) in a form-fitting manner and is thus centred in both axial directions (A1, A2).

Description

[0001] Wheel bearing unit, in particular for a motor vehicle

[0002] The invention relates to a wheel bearing unit, in particular for a motor vehicle, with an outer ring and an inner ring fixed on a wheel hub, as well as a sealing device provided between the outer ring and the wheel hub according to claim 1.

[0003] Sealing devices of this type for wheel bearing units are known from the prior art. These sealing devices are fixed on the wheel side between an outer ring and a wheel hub, and on the transmission side between the outer ring and an inner ring pressed onto the wheel hub. Typically, the sealing devices consist of a sealing element and a disc element. The sealing element is fixed to the outer ring, and the disc element to the wheel hub or inner ring. The sealing element and / or the disc element have sealing parts, such as sealing lips, that seal between the two parts to prevent dirt and water from penetrating the wheel bearing. Such sealing devices are known, for example, from DE 10 2018 107 772.

[0004] The disc element is preferably fixed to the wheel hub in a force-locking manner by means of a press fit. High rotating bending moments on the wheel hub cause severe deformations in the contact zone between the wheel hub and the disc element. These deformations, in the form of compression or expansion, increase the risk of the disc element being set into rotational or axial movement. DE 10 2021 105 258 A1 discloses a disc element that has a rubberized seating area and a pure sheet metal seat on the flange. In this case, micro-movements can be transmitted to the disc element via the wheel hub or the flange, which also sets it into axial movement. Due to this so-called sheet metal creep, the disc element moves axially in the direction of the rolling elements and can thus damage the bearing. Various solutions exist in the state of the art to prevent sheet metal creep.For example, DE 10 2013 218 635 proposes a flange on the wheel hub to limit axial movement. Due to increasing demands (e.g., higher loads), the risk increases that the interference fit of the disc element will lose its static sealing effect due to deformation of the wheel hub or flange. Furthermore, contact corrosion can occur between the disc element and the wheel hub, as both parts are made of metal. Furthermore, the transmission of micromovements from the wheel hub flange to the disc element should be reliably prevented in order to avoid axial creep and thus increase the service life of the bearing.

[0005] The object of the invention is therefore to solve these problems and ensure a long service life of the wheel bearings. In particular, axial movement of the disc element should be prevented and the sealing effect guaranteed. Furthermore, the disc element should be securely centered on the wheel hub in both axial directions.

[0006] The problem is solved by a wheel bearing unit according to claim 1.

[0007] The wheel bearing unit according to the invention, in particular for a motor vehicle, comprises an outer ring and an inner ring fixed on a wheel hub, wherein a sealing device is provided between the outer ring and the wheel hub, wherein the sealing device comprises at least one sealing element and a disc element, wherein the sealing element is fastened to the outer ring and the disc element to the wheel hub, wherein the disc element has an axial part and a radial part. According to the invention, the disc element is completely provided with a coating on the axial part on the surface facing the wheel hub, and the disc element is positively connected to the wheel hub and is thus centered in both axial directions.

[0008] The coating of the disc element according to the invention decouples the micro-movements from the flange of the disc element. This prevents axial movement of the disc element. Furthermore, the insulating properties of the coating eliminate the transmission of micro-movements of the disc element. The positive connection between the disc element and the wheel hub allows the disc element to be secured and centered in both axial directions.

[0009] Preferably, at least one guide groove is provided on the wheel hub and / or the coating.

[0010] The guide groove can be any type of recess that allows the disc element to be secured or centered in both axial directions. The guide groove can be annular around the entire circumference. However, it would also be conceivable for several guide grooves to be distributed around the circumference.

[0011] It can also be a groove or a recess with a continuous depression. The guide groove can be provided on the wheel hub and / or on the coating. The guide groove and the stresses created by the coating generate axial forces on both sides of the disc element. These axial forces center the disc element on the wheel hub, thus ensuring its position.

[0012] In a preferred embodiment, the coating is a polymer, particularly an elastomer. The damping properties of the polymer or elastomer prevent the transmission of vibrations to the disc element.

[0013] In principle, any basic elastomer material is suitable for the sealing body. Nitrile rubber, such as NBR (Nitrile Butadiene Rubber), is particularly suitable. HNBR (Hydrogenated Acrylonitrile Butadiene Rubber), FKM (Fluorocarbon Rubber), ACM (Polyacrylate Rubber), EPDM (Ethylene Propylene Diene Monomer Rubber), or the like are also conceivable. Thermoplastic elastomers such as TPE, TPU, TPA, etc., or blends of the aforementioned materials, could also be used. In a preferred embodiment of the invention, the guide groove is provided on the wheel hub and interacts with a corresponding elevation of the coating.

[0014] It is also conceivable that the guide groove is provided on the coating and interacts with a corresponding elevation on the wheel hub. The elevation could be, for example, a projection or a plateau. All forms of elevations and guide grooves are conceivable.

[0015] Particularly preferably, a guide groove is provided on both the wheel hub and the coating, which are arranged offset from one another and provided with corresponding recesses

[0016] In a further preferred embodiment, at least two axially offset guide grooves are arranged one behind the other. A raised portion is preferably formed between the guide grooves. This allows for a particularly secure fit between the disc element and the wheel hub, thereby improving the axial centering of the disc element.

[0017] According to one embodiment, the guide groove can be concave or convex. These can interact with complementary elevations to axially secure the disc element.

[0018] In a further preferred embodiment, the radial part of the disc element is, in particular, completely coated on the surface facing the wheel hub. The coating of the disc element is provided completely on the surface facing the wheel hub, i.e., over the entire surface. The complete coating on the side facing the wheel hub results in good material flow during production.

[0019] The sealing element preferably has at least one seal carrier and at least one sealing lip. The seal carrier is preferably attached to the outer ring. Particularly preferably, the sealing element has a plurality of sealing lips, of which at least one sealing lip preferably extends in the axial direction, such that the sealing lip comes into contact with the disc element.

[0020] In a further embodiment of the invention, the coating has an axial sealing lip that is in axial contact with a radial section of the wheel hub. The axial sealing lip can further prevent the penetration of dirt and water.

[0021] Further measures improving the invention are described in more detail below together with the description of two preferred embodiments of the invention with reference to the figures, wherein identical or similar components are provided with the same reference numerals.

[0022] Figure 1 shows a section of a wheel bearing with a sealing arrangement according to the invention according to a first embodiment,

[0023] Figure 2 shows a section of a wheel bearing with a sealing arrangement according to the invention according to a second embodiment

[0024] Figure 3 shows a section of a wheel bearing with a sealing arrangement according to the invention according to a third embodiment

[0025] Figure 1 shows an exemplary wheel bearing 10, in particular for a motor vehicle, with an outer ring 2 and a wheel hub 3. An inner ring (not shown) is pressed onto the wheel hub 3. At least two rows of rolling elements are mounted between the outer ring 2 and the wheel hub 3. Furthermore, a sealing device is provided between the outer ring 2 and the wheel hub 3, which is intended to prevent the penetration of dirt and water into the bearing. The sealing device 1 has a sealing element 4. The sealing element 4 comprises a seal carrier 4a, which is fastened to the outer ring 2. The seal carrier 4a also has a seal that includes at least one sealing lip 4b. The seal of the seal carrier 4a preferably includes at least one sealing lip 4b, which is in sliding contact with a disk element 5. The seal preferably has further contactless sealing lips that form a labyrinth seal.As shown in Figure 1, the seal carrier 4a can be fixed to the end face of the outer ring 2. The seal carrier 4a can also include an extension 4c that extends in the axial direction A toward a radial portion of the wheel hub 3. The extension 4c can further prevent the ingress of water and dirt. It would also be conceivable for the seal carrier 4c to be fixed to the outside or inside of the outer ring 2.

[0026] The disc element 5 comprises a carrier and a coating 6 applied thereto. The carrier of the disc element 5 is preferably made of metal, such as sheet metal, or plastic. The disc element 5 can be L-shaped. The disc element 5 has an axial part 5a and a radial part 5b which extends in the radial direction R from the axial part 5a. The disc element 5 is mounted on the wheel hub 3 and forms a static sealing seat. The sealing lip 4b of the sealing element 4 rests against the radial part 5b of the disc element 5. However, the disc element 5 can also be C-shaped, wherein the disc element, in addition to the axial part 5a and the radial part 5b, also has a second axial part 5c which extends radially between the outer ring 2 and the axial part 5a of the disc element 5 in the direction of the sealing element 4.This second axial part 5c can also have the coating 6 on the surface facing the outer ring 2 and / or the sealing element 4. Furthermore, the second axial part 5c can consist only of the coating 6 and no longer have a carrier element.

[0027] The coating 6 of the disc element 5 is preferably formed from a polymer. Particularly preferably, the coating 6 is an elastomer or a rubber coating. The axial part 5a of the disc element 5 is completely coated on the surface facing the wheel hub 3. The complete coating 6 of the axial part 5a of the disc element 5 has the advantage that micro-movements transmitted from the flange of the wheel hub are dampened, thereby preventing axial migration of the disc element 5. As can be seen in Figure 1, the wheel hub 3 has a radial section. The radial part 5b of the disc element 5 is preferably completely provided with the coating 6 on the surface facing the radial section. The coating 6 can also have an axial sealing lip (not shown here) protruding from the radial part 5b, which contacts the radial section of the wheel hub 3.

[0028] The disc element 5 is positively connected to the wheel hub 3. As can be seen in Figure 1, the wheel hub 3 has guide grooves 7 for this purpose. The guide grooves 7 can be designed in the form of a recess of any desired design. Particularly preferably, several, in particular two or three, guide grooves 7 are arranged one behind the other. The disc element 5 has elevations 8 complementary to the guide grooves 7. In particular, several elevations 8 are formed one behind the other on the disc element or the coating 6, which engage in the complementary guide grooves 7. In this way, the disc element 5 can be centered and fixed on the wheel hub in both axial directions A1 and A2. The connection between the disc element 5 and the wheel hub is thus force-fitting and form-fitting.

[0029] Figure 2 shows a second embodiment of the positive connection between disc element 5 and wheel hub 3. Here, a protrusion 8 is formed on the wheel hub 3, which engages in a guide groove 7 of the coating 6 in order to axially center the disc element 5. For this purpose, the coating 6 has axial extensions in both directions next to the guide groove, which bear against the wheel hub 3. It would also be conceivable for the wheel hub 3 to have a guide groove 7 that interacts with a complementarily formed protrusion 8 of the coating 6.

[0030] Figure 3 shows a further embodiment. The guide groove 7 on the coating 6 is concave here and engages with a complementary convex elevation 8 on the wheel hub 3. However, it would also be conceivable for the guide groove 7 on the wheel hub 3 to be concave and interact with a complementary convex elevation 8 on the coating 6. List of reference symbols

[0031] 1 sealing device

[0032] 2 Outer ring 3 Wheel hub

[0033] 4 Sealing element

[0034] 4a Seal carrier

[0035] 4b Sealing lip

[0036] 4c Extension 5 Disc element

[0037] 5a Axial part

[0038] 5b Radial part

[0039] 5c Second axial part

[0040] 6 Coating 7 Guide groove

[0041] 8 Survey

[0042] A1 , A2 Axial directions

[0043] R Radial direction

Claims

Patent claims 1. Wheel bearing unit (10), in particular for a motor vehicle, with an outer ring (2) and an inner ring fixed on a wheel hub (3), wherein a sealing device (1) is provided between the outer ring (2) and the wheel hub (3), wherein the sealing device (1) comprises at least one sealing element (4) and a disc element (5), wherein the sealing element (4) is fastened to the outer ring (2) and the disc element (5) is fastened to the wheel hub (3), wherein the disc element (5) has an axial part (5a) and a radial part (5b), characterized in that the disc element (5) is completely provided with a coating (6) on the axial part (5a) on the surface facing the wheel hub (3) and the disc element (5) is positively connected to the wheel hub (3) and is thus centered in both axial directions (A1, A2).

2. Wheel bearing unit (10) according to claim 1, characterized in that at least one guide groove (7) is provided on the wheel hub (3) and / or the coating (6).

3. Wheel bearing unit (10) according to claim 1 or 2, characterized in that the coating (6) is formed from a polymer, in particular from an elastomer.

4. Wheel bearing unit (10) according to claim 2, characterized in that the guide groove (7) is provided on the wheel hub (3) and cooperates with a corresponding elevation (8) of the coating (6).

5. Wheel bearing unit (10) according to claim 1 or 2, characterized in that the guide groove (7) is provided on the coating (6) and cooperates with a corresponding elevation (8) of the wheel hub (3).

6. Wheel bearing unit (10) according to claim 1 or 2, characterized in that at least two axially offset guide grooves (7) are arranged one behind the other.

7. Wheel bearing unit (10) according to one of the preceding claims, characterized in that the at least one guide groove (7) is concave.

8. Wheel bearing unit (10) according to one of the preceding claims, characterized in that the at least one guide groove (7) is convex.

9. Wheel bearing unit (10) according to one of the preceding claims, characterized in that the radial part (5b) on the surface facing the wheel hub (3) is completely provided with the coating (6).

10. Wheel bearing unit (10) according to one of the preceding claims, characterized in that the coating (6) has a second axial part (5c) which projects in an axial direction A1 at the radial end of the radial part (5b) in the direction of the sealing element (4).

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