Wheel bearing unit, especially for a motor vehicle

Abstract

The invention relates to a 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 attached to the outer ring (2) and the disc element (5) is attached to the wheel hub (3), wherein the disc element (5) has an axial part (5a) and a radial part (5b), wherein the disc element (5) is completely provided with a coating (6) on the surface facing the wheel hub (3) on the axial part (5a) and the disc element (5) is positively connected to the wheel hub (3) and is thus centered in both axial directions (A1, A2).

Description

[0001] The invention relates to a wheel bearing unit, in particular for a motor vehicle, comprising 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.

[0002] Typical sealing devices 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. The sealing devices usually 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 the inner ring. The sealing element and / or the disc element have sealing components, such as sealing lips, that seal between the two parts to prevent the ingress of dirt and water into the wheel bearing. Such sealing devices are known, for example, from DE 10 2018 107 772.

[0003] The disc element is preferably fixed to the wheel hub by means of a frictional press fit. High rotating bending moments at the wheel hub cause significant deformations in the contact zone between the wheel hub and the disc element. These deformations, in the form of compression or elongation, increase the risk of the disc element being set into rotational or axial motion. A disc element is known from DE 10 2021 105 258 A1, which has a rubberized seating area and a 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, causing it to also be set into axial motion. This so-called sheet metal wander causes the disc element to move axially towards the rolling elements and can damage the bearing. Various solutions exist in the prior art to prevent sheet metal wander.For example, the publication DE 10 2013 218 635 proposes a rim on the wheel hub that limits the axial movement.

[0004] Due to increasing demands (e.g., higher loads), the risk increases that the press 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. In addition, the transmission of micro-movements from the wheel hub flange to the disc element must be reliably prevented to avoid axial movement and thus extend the bearing's service life.

[0005] The object of the invention is therefore to solve these problems and ensure a long service life for the wheel bearings. In particular, the axial movement of the disc element should be prevented and the sealing effect guaranteed. Furthermore, the disc element should be reliably 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, particularly for a motor vehicle, comprises an outer ring and an inner ring fixed to a wheel hub, wherein a sealing device is provided between the outer ring and the wheel hub, the sealing device comprising at least one sealing element and a disc element, the sealing element being attached to the outer ring and the disc element to the wheel hub, the disc element having an axial part and a radial part. According to the invention, the disc element is completely coated on the surface of the axial part facing the wheel hub and is positively connected to the wheel hub, thus being centered in both axial directions.

[0008] The coating of the disc element according to the invention decouples the micro-movements of the flange from 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-locking connection between the disc element and the wheel hub secures and centers the disc element 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 ring-shaped around the entire circumference. However, it is also conceivable that several guide grooves are arranged distributed around the circumference.

[0011] It can be a groove or a recess with a continuous downward slope. The guide groove can be located 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, in particular 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 element. Nitrile rubber, such as NBR (Nitrile Butadiene Rubber), is particularly suitable. Other possibilities include HNBR (Hydrogenated Acrylonitrile Butadiene Rubber), FKM (Fluorocarbon Rubber), ACM (Polyacrylate Rubber), EPDM (Ethylene Propylene Diene Monomer Rubber), and similar materials. Thermoplastic elastomers, such as TPE, TPU, TPA, etc., or even blends of the aforementioned materials could also be used.

[0014] In a preferred embodiment of the invention, the guide groove is provided on the wheel hub and interacts with a corresponding protrusion in the coating.

[0015] Furthermore, it is conceivable that the guide groove is integrated into the coating and interacts with a corresponding protrusion on the wheel hub. This protrusion could be, for example, a projection or a plateau. All forms of protrusions and guide grooves are possible.

[0016] Particularly preferred is the provision of a guide groove on both the wheel hub and the coating, which are arranged offset from each other and have corresponding recesses.

[0017] In a further preferred embodiment, at least two axially offset guide grooves are arranged one behind the other. A raised section is preferably formed between the guide grooves. This allows for a particularly secure positive fit between the disc element and the wheel hub, thereby improving the axial centering of the disc element.

[0018] The guide groove can be concave or convex according to one embodiment. These can interact in complementary forms and axially secure the disc element.

[0019] 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, i.e., over the entire surface, on the surface facing the wheel hub. This complete coating on the side facing the wheel hub results in good material flow during manufacturing.

[0020] Preferably, the sealing element comprises at least one sealing carrier and at least one sealing lip. The sealing carrier is preferably attached to the outer ring. Particularly preferably, the sealing element has several sealing lips, at least one of which preferably extends in the axial direction such that the sealing lip comes into contact with the disc element.

[0021] 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 further prevents the ingress of dirt and water.

[0022] Further measures improving the invention are described in more detail below, together with a 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. Fig. 1 a section of a wheel bearing with a sealing arrangement according to the invention in a first embodiment, Fig. 2 a section of a wheel bearing with a sealing arrangement according to the invention in a second embodiment Fig. 3 a section of a wheel bearing with a sealing arrangement according to the invention in a third embodiment

[0023] Fig. Figure 1 shows an exemplary wheel bearing 10, particularly 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 to prevent the ingress 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 attached to the outer ring 2. The seal carrier 4a also has a seal comprising at least one sealing lip 4b. Preferably, the seal of the seal carrier 4a comprises at least one sealing lip 4b, which is in sliding contact with a disk element 5. Preferably, the seal has further non-contacting sealing lips that form a labyrinth seal. As shown in Figure 1, the seal carrier 4a has at least one sealing lip 4b that is in sliding contact with a disk element 5. Preferably, the seal has further non-contacting sealing lips that form a labyrinth seal. Fig. As shown in Figure 1, the sealing carrier 4a can be fixed to the end face of the outer ring 2. The sealing carrier 4a can also include a projection 4c that extends axially in direction A towards a radial section of the wheel hub 3. The projection 4c further prevents the ingress of water and dirt. It would also be conceivable for the sealing carrier 4c to be fixed to the outside or inside of the outer ring 2.

[0024] 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 radially 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, in which case, in addition to the axial part 5a and the radial part 5b, the disc element 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 solely of the coating 6 and no longer have a support element.

[0025] 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 damped, thereby preventing axial movement of the disc element 5. As in Fig. 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 covered with the coating 6 on the surface facing the radial section. The coating 6 may also have an axial sealing lip projecting from the radial part 5b (not shown here), which contacts the radial section of the wheel hub 3.

[0026] The disc element 5 is positively connected to the wheel hub 3. As in Fig. 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 shape. Particularly preferably, several, especially two or three, guide grooves 7 are arranged one behind the other. The disc element 5 has projections 8 that are complementary to the guide grooves 7. In particular, several projections 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-fit and form-fit.

[0027] Fig. Figure 2 shows a second embodiment of the positive-locking connection between disc element 5 and wheel hub 3. Here, a projection 8 is formed on the wheel hub 3, which engages in a guide groove 7 of the coating 6 to axially center the disc element 5. For this purpose, the coating 6 has extensions axially 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 complementary projection 8 of the coating 6.

[0028] In Fig.Figure 3 shows a further embodiment. Here, the guide groove 7 on the coating 6 is concave and engages with a complementary convex projection 8 on the wheel hub 3. However, it would also be conceivable that the guide groove 7 on the wheel hub 3 is concave and interacts with a complementary convex projection 8 on the coating 6. Reference symbol list 1 sealing device 2 outer ring 3 Wheel hub 4 Sealing element 4a Seal carrier 4b Sealing lip 4c extension 5 disc element 5a Axial part 5b Radial part 5c Second axial part 6 coating 7 Guide groove 8 Survey A1, A2 Axial directions R Radial direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 107 772

[0002] DE 10 2021 105 258 A1

[0003] DE 10 2013 218 635

[0003]

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) to the wheel hub (3), wherein the disc element (5) has an axial part (5a) and a radial part (5b), characterized by 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 bythat 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 by that the coating (6) is formed from a polymer, in particular from an elastomer. [4] Wheel bearing unit (10) according to claim 2, characterized by that the guide groove (7) is provided on the wheel hub (3) and interacts with a corresponding elevation (8) of the coating (6). [5] Wheel bearing unit (10) according to claim 1 or 2, characterized by that the guide groove (7) is provided on the coating (6) and interacts with a corresponding elevation (8) of the wheel hub (3). [6] Wheel bearing unit (10) according to claim 1 or 2, characterized by 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 bythat the at least one guide groove (7) is concave. [8] Wheel bearing unit (10) according to one of the preceding claims, characterized by that the at least one guide groove (7) is convex. [9] Wheel bearing unit (10) according to one of the preceding claims, characterized by 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 by 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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