Wheel bearing unit, in particular for 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 fastened to a hub (3), a sealing device (1) being arranged between the outer ring (2) and the hub (3), the sealing device (1) comprising at least one sealing element (4) and a disc-shaped element (5), the sealing element (4) being arranged between the outer ring (2) and the hub (3), and the disc-shaped element (5) being arranged between the outer ring (2) and the hub (3). The sealing element (4) is fastened to the outer ring (2) and the disk-like element (5) is fastened to the hub (3), where the disk-like element (5) has an axial portion (5a) and a radial portion (5b), and where the disk-like element (5) is entirely provided with a coating (6) on the axial portion (5a) on a surface facing the hub (3).

Description

Technical Field

[0001] The present invention relates to a wheel bearing unit according to claim 1, in particular for a motor vehicle, having an outer ring and an inner ring fixed to a wheel hub, and a sealing device arranged between the outer ring and the wheel hub. Background Art

[0002] Generic sealing devices for wheel bearing units are known from the prior art. These sealing devices are fixed on the wheel side between the outer ring and the wheel hub and on the transmission side between the outer ring and the inner ring pressed onto the wheel hub. The sealing device typically includes a sealing element and a disk-shaped element. The sealing element is fixed to the outer ring, and the disk-shaped element is fixed to the wheel hub or the inner ring. In this case, the sealing element and / or the disk-shaped element has a sealing portion, such as a sealing lip, which provides a seal between the two parts to prevent dirt and water from entering the wheel bearing. For example, such a sealing device is known from DE 10 2018 107 772.

[0003] The disk-shaped element is preferably fixed to the wheel hub in a force-fitting manner. The high rotational bending torque on the wheel hub causes severe deformation in the contact area between the wheel hub and the disk-shaped element. These deformations in the form of compression or elongation increase the risk of rotational or axial movement of the disk-shaped element. DE 10 2021 105258A1 discloses a disk-shaped element having a rubberized seat area and a pure metal sheet seat on a flange. Here, micro-movements can be transmitted via the wheel hub or the flange to the disk-shaped element, which also causes axial movement of the disk-shaped element. This so-called plate creep causes the disk-shaped element to move axially in the direction of the rolling elements and may damage the bearing. Various solutions are known from the prior art to prevent such plate creep. For example, DE 10 2013 218 635 discloses an edge that limits axial movement on the wheel hub.

[0004] Increased requirements (e.g., higher loads) increase the risk that the press fit of the disk-shaped element loses its static sealing effect due to deformation of the wheel hub or the flange. In addition, contact corrosion may occur between the disk-shaped element and the wheel hub because both parts are made of metal. Additionally, micro-movements of the flange of the wheel hub should be reliably prevented from being transmitted to the disk-shaped element in order to avoid axial movement and thus increase the service life of the bearing. Summary of the Invention

[0005] Therefore, the object of the present invention is to solve these problems and ensure a long service life of the wheel bearing. In particular, axial movement of the disk-shaped element should be prevented in this regard and the sealing effect should be ensured.

[0006] This object is achieved by a wheel bearing unit according to claim 1.

[0007] A wheel bearing unit according to the present invention, in particular 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, wherein the sealing device comprises at least one sealing element and a disc-shaped element, wherein the sealing element is fastened to the outer ring and the disc-shaped element is fastened to the wheel hub, and wherein the disc-shaped element has an axial portion and a radial portion. According to the invention, the disc-shaped element is completely provided with a coating on the surface facing the wheel hub on the axial portion.

[0008] The coating of the disc-shaped element according to the invention decouples the micro-movement of the flange from the disc-shaped element. This prevents the axial movement of the disc-shaped element.

[0009] 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-shaped element.

[0010] In principle, any base elastomer material is suitable as the material for the sealing body. Nitrile rubber, such as NBR (acrylonitrile-butadiene rubber), is particularly suitable. It is also conceivable to use HNBR (hydrogenated acrylonitrile-butadiene rubber), FKM (fluorocarbon rubber), ACM (acrylate rubber), EPDM (ethylene propylene diene monomer rubber), etc. "Thermoplastic elastomers", such as TPE, TPU, TPA, etc. or even mixtures of the above materials can also be used.

[0011] In another preferred embodiment, the radial portion of the disc-shaped element is provided with a coating, particularly completely provided with a coating, on the surface facing the wheel hub. The coating of the disc-shaped element is completely provided on the surface facing the wheel hub, i.e., the entire surface. The complete coating on the side facing the wheel hub results in good material flow during production.

[0012] Preferably, the coating on the axial portion of the disc-shaped element has a structure, in particular grooves. In this regard, a plurality of grooves can be provided, and the plurality of grooves are arranged at equal or irregular distances from each other. The grooves generate greater friction, which makes it more difficult for the disc-shaped element to shift.

[0013] In one embodiment of the invention, the wheel hub has a structure, in particular grooves, at least in the region in contact with the coating. Preferably, a plurality of grooves are provided, but at least two grooves. The grooves can be arranged at equal or irregular distances from each other. The grooves are preferably ground. Due to the grooves in the contact region of the wheel hub, the coating, in particular the elastic rubber, will deform due to overlapping with the grooves or slots. This forms a certain form fit. This makes it even easier to prevent the disc-shaped element from shifting. For example, the structure can be introduced by grinding or an additional turning process.

[0014] In another embodiment of the present invention, the coating on the axial portion of the disc-shaped element has a cylindrical portion and an adjacent conical portion, wherein the conical portion of the coating widens at an angle between 1° and 5°. This angle relates to the horizontal plane of the surface of the hub on which the disc-shaped element sits. The conical extension on the coating prevents the disc-shaped element from tilting during assembly. This improves the static fit of the disc-shaped element.

[0015] Preferably, the sealing element has 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 a plurality of sealing lips, and preferably at least one of the plurality of sealing lips extends in the axial direction such that the sealing lip contacts the disc-shaped element.

[0016] In another embodiment of the present invention, the coating further has an axial sealing lip that contacts the radial section of the hub in the axial direction. The axial sealing lip can also prevent the entry of dirt and water.

[0017] Preferably, the hub and the disc-shaped element are particularly connected to each other in a form-fitting and / or force-fitting manner via their structures. It is conceivable that the hub has a groove that interacts with the complementary protrusion of the coating of the disc-shaped element. This solution can further improve the static sealing seat of the disc-shaped element. Description of the Drawings

[0018] The following describes in more detail other measures for improving the present invention and the descriptions of two preferred exemplary embodiments of the present invention, wherein the same or similar elements are provided with the same reference numerals. In the drawings:

[0019] Figure 1 shows a cross-section of a wheel bearing with a sealing device according to the present invention,

[0020] Figure 1a shows a detailed view of a cross-section of a disc-shaped element from Figure 1 the

[0021] Figure 2 shows a detailed view of a cross-section of a disc-shaped element and a hub according to a second embodiment,

[0022] Figure 3 shows a detailed view of a cross-section of a disc-shaped element and a hub according to a third embodiment,

[0023] Figure 3a shows a detailed view of a cross-section of a disc-shaped element and a hub according to a fourth embodiment,

[0024] Figure 4 shows a detailed view of a cross-section of a disc-shaped element and a hub according to a fifth embodiment. Detailed implementation mode

[0025] Figure 1 An exemplary wheel bearing 10 is shown, especially a wheel bearing for a motor vehicle, which has an outer ring 2 and a hub 3. The inner ring (not shown) is pressed onto the hub 3. At least two rows of rolling elements 7 are installed between the outer ring 2 and the hub 3. In addition, a sealing device is provided between the outer ring 2 and the hub 3 to prevent dirt and water from entering the bearing. The sealing device 1 has a sealing element 4. The sealing element 4 includes a sealing carrier attached to the outer ring 2. The sealing carrier also includes a seal having at least one sealing lip. Preferably, the seal of the sealing carrier includes at least one sealing lip that slidably contacts the disc-shaped element 5. Preferably, the seal also has a non-contact sealing lip that forms a labyrinth seal. As shown in Figure 1 As shown, the sealing carrier can be fixed to the end face of the outer ring 2. The sealing carrier can also include a sealing extension that extends in the axial direction A towards the radial section 3b of the hub 3. The sealing extension can also prevent the entry of water and dirt. It is also conceivable that the sealing carrier is fixed to the outer or inner part of the outer ring 2.

[0026] The disc-shaped element 5 includes a carrier and a coating 6 applied to the carrier. The carrier of the disc-shaped element is preferably made of metal, such as sheet metal or plastic. The disc-shaped element 5 can be designed in an L-shaped configuration. The disc-shaped element 5 has an axial portion 5a and a radial portion 5b, and the radial portion extends radially from the axial portion 5a in the radial direction R. The disc-shaped element 5 is pressed onto the hub 3 and forms a static sealing seat. The sealing lip of the sealing element 4 contacts the radial portion 5b of the disc-shaped element 5. However, the disc-shaped element 5 can also be designed in a C-shaped configuration, in which the disc-shaped element has a second axial portion 5d in addition to the axial portion 5a and the radial portion 5b, and the second axial portion extends radially between the outer ring and the axial portion 5a of the disc-shaped element in the direction of the sealing element 4. The second axial portion 5d can also have a coating 6 on the surface facing the outer ring 2 and / or the sealing element 4.

[0027] The coating 6 of the disc-shaped element 5 is preferably formed of a polymer. The coating 6 is particularly preferably an elastomeric or rubber coating. The axial portion 5a of the disc-shaped element 5 completely covers the surface facing the hub 3. The complete coating 6 of the axial portion 5a of the disc-shaped element 5 has the advantage that the micro-movement transmitted through the flange of the hub is damped, thereby preventing the axial movement of the disc-shaped element 5. As can be seen in Figure 1 As can be seen, the hub 3 has a radial section 3b. The radial portion 5b of the disc-shaped element 5 is preferably completely provided with the coating 6 on the surface facing the radial section 3b. The coating 6 also has an axial sealing lip 6d protruding from the radial portion 5b, and the axial sealing lip contacts the radial section 3b of the hub 3.

[0028] Figure 1a Shows in detail the position of the disc-shaped element 5 on the hub 3. What can be seen here is that the carrier of the disc-shaped element 5 is attached to the generally cylindrical surface of the hub 3 through its axial portion 5a. The radial portion 5a is adjacent to the axial portion 5a via an inclined transition region or a ramp transition region 5c. The region of the axial portion 5a facing the hub 3, the transition region, and the radial portion 5b are all completely provided with a coating 6.

[0029] Figure 2 Shows a second embodiment of the coating 6 on the sealing device 1. The coating 6 on the axial portion 5a of the disc-shaped element 5 has a structure 6a. The structure preferably includes a plurality of grooves. The plurality of grooves is understood to mean at least two grooves. In particular, the grooves are arranged at equal distances from each other. However, it is also conceivable that the grooves are arranged at irregular distances from each other. As can be seen in Figure 2 the coating 6 extends over the axial portion 5a and the transition region 5c.

[0030] Figure 3 Shows a third embodiment of the present invention. The disc-shaped element 5 is designed as described in Figure 1 The hub 3 has a structure 3a in the region in contact with the coating of the disc-shaped element 5. The structure can be designed as, for example, a plurality of grooves. The structure is ground into the surface of the hub 3.

[0031] Figure 3a Shows a structure similar to that of Figure 3 . However, in addition to the coating 6, extensions 5e are provided on the axial portion 5a and in the transition region 5c. The extensions 5e are preferably designed as rubber coatings. The hub 3 has a radius in the transition region between the surface in contact with the disc-shaped element 5 and the radial section 5b. According to Figure 3a , the extension 6e of the coating 6 at least partially contacts the radius of the hub 3. The extension 6e serves as an additional sealing portion and also supports the fixing function and positioning due to the form fit.

[0032] Figure 4 Shows another embodiment according to the present invention. The coating 6 on the disc-shaped element 5 has a cylindrical portion 6b and an adjacent conical portion 6c. The conical portion 6c widens uniformly at an angle α between 1° and 5° with respect to a horizontal line that is substantially parallel to the axis of the wheel bearing. The conical portion 6c of the coating 6 prevents the disc-shaped element 5 from tilting during assembly and ensures that the disc-shaped element 5 sits firmly.

[0033] List of reference numerals

[0034] 1 Sealing device

[0035] 2 Outer ring

[0036] 3 Hub

[0037] 3a Structure

[0038] 3b Radial Segment

[0039] 4 Sealing Element

[0040] 5 Disk-shaped Element

[0041] 5a Axial Portion

[0042] 5b Radial Portion

[0043] 5c Transition Region

[0044] 5d Second Axial Portion

[0045] 6 Coating

[0046] 6a Structure

[0047] 6b Cylindrical Portion

[0048] 6c Tapered Portion

[0049] 6d Axial Sealing Lip

[0050] 6e Extension

[0051] 7 Rolling Element

[0052] A Axial Direction

[0053] R Radial Direction

Claims

1. A wheel bearing unit (10), in particular for a motor vehicle, having an outer ring (2) and an inner ring fixed to a wheel hub (3), wherein, A sealing device (1) is provided between the outer ring (2) and the hub (3), wherein the sealing device (1) comprises at least one sealing element (4) and a disc-shaped element (5), wherein the sealing element (4) is fastened to the outer ring (2) and the disc-shaped element (5) is fastened to the hub (3), wherein the disc-shaped element (5) has an axial portion (5a) and a radial portion (5b), characterized in that the disc-shaped element (5) is completely provided with a coating (6) on the surface facing the hub (3) on the axial portion (5a).

2. The wheel bearing unit (10) according to claim 1, characterized in that, The coating (6) is formed of a polymer, in particular an elastomer.

3. The wheel bearing unit (10) according to claim 2, characterized in that, The elastomer is NBR or FKM.

4. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that The radial portion (5b) is provided with, in particular completely provided with, a coating (6) on the surface facing the hub (3).

5. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The coating (6) has a structure (6a), in particular a groove, on the axial portion (5a).

6. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The hub (3) has a structure (3a), in particular a groove, at least in the region in contact with the coating (3).

7. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The coating (6) has a cylindrical portion (6b) and an adjoining conical portion (6c), wherein the conical portion (6c) of the coating (6) widens at an angle (α) between 1° and 5°.

8. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The sealing element (4) has at least one sealing carrier (4a) and at least one sealing lip (4b).

9. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The coating (6) also has an axial sealing lip (6d) which contacts a radial section (3b) of the hub (3) in the axial direction A.

10. The wheel bearing unit (10) according to any one of the preceding claims, characterized in that, The hub (3) and the disc-shaped element (5) are connected to each other in a form-fitting and / or force-fitting manner, in particular via the structures of the hub and the disc-shaped element.

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