Wheel bearing unit for a motor vehicle

Abstract

The invention relates to a wheel bearing unit for a motor vehicle, comprising 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 or the inner ring, wherein the sealing device comprises at least one sealing element and a disc element, wherein the sealing element is attached to the outer ring and the disc element to the wheel hub or the inner ring, wherein the disc element has an axial part and a radial part, and wherein the sealing element has an axial part and a radial part, wherein the axial part of the disc element is completely rubberized on the surface facing the inner ring or the wheel hub and / or that the axial part of the sealing element is completely rubberized on the surface facing the outer ring.

Description

[0001] The invention relates to a wheel bearing unit for a motor vehicle, comprising 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 or the inner ring, wherein the sealing device comprises at least one sealing element and a disc element, wherein the sealing element is attached to the outer ring and the disc element to the wheel hub or the inner ring, wherein the disc element has an axial part and a radial part, and wherein the sealing element has an axial part and a radial part.

[0002] Wheel bearing units of this type are well known from the prior art. German patent application DE 10 2016 125 093 A1 discloses such a wheel bearing unit in which a sealing device is provided between the outer ring and the inner ring or wheel hub. It can be seen that the seal carrier is pressed into the outer ring and a disc element into the inner ring. The seal carrier and disc element are typically fixed to the outer ring and inner ring, respectively, by an interference fit. To enable this, the contact surfaces of the outer and inner rings must be ground. This also prevents corrosion caused by penetrating dirty water.

[0003] However, grinding the surfaces of the outer and inner rings requires an additional manufacturing step and is complex. Therefore, a more cost-effective way is being sought to prevent corrosion at these points and thus increase the service life of the wheel bearing.

[0004] The problem is solved by a wheel bearing unit according to claim 1. Further advantageous embodiments are set out in the dependent claims.

[0005] The wheel bearing unit according to the invention 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 or the inner ring, 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 being attached to the wheel hub or the inner ring, the disc element having an axial part and a radial part, and the sealing element having an axial part and a radial part. According to the invention, the axial part of the disc element is completely rubberized on the surface facing the inner ring or the wheel hub and / or the axial part of the sealing element is completely rubberized on the surface facing the outer ring.

[0006] By completely rubberizing the contact surface of the axial part facing the inner or outer ring, corrosion undercutting is prevented. Furthermore, grinding the contact surfaces on the outer or inner ring or wheel hub is unnecessary, making the wheel bearing simpler and therefore more cost-effective to manufacture overall.

[0007] Preferably, the contact surface of the outer ring to the axial part of the sealing element and / or the contact surface of the inner ring or the wheel hub to the axial part of the disc element is unground. The contact surfaces are thus turned, but not ground.

[0008] The radial thickness of the rubber lining mitigates the larger radial tolerances (resulting from the elimination of the grinding process) of the contact surfaces in the outer or inner ring and their influence on the press fit. Depending on the tolerance of the turned contours on the outer and / or inner ring, the rubber lining is compressed more or less, ensuring proper assembly and a secure fit of the sealing elements.

[0009] According to one embodiment of the invention, it is preferred that the contact surface of the outer ring with the axial part of the sealing element and / or the contact surface of the inner ring or the wheel hub with the axial part of the disc element has a roughness (roughness depth Rz) between 6.3 and 25 µm. The surface can thus be significantly rougher than in the prior art, since corrosion penetration is not possible due to the fully rubberized surface of the axial part of the disc element or the sealing element.

[0010] Preferably, an inlet gap is provided between the sealing element and the disc element, in which a labyrinth seal is formed. The inlet gap is preferably designed in the axial direction and can make it more difficult for dirt and water to enter.

[0011] In one embodiment of the invention, the disk element has an encoder on its radial part which extends in a radial direction at least to the level of the outer ring.

[0012] Preferably, the encoder and / or the radial part of the disc element extends radially at least to the level of the outer ring. Extending the encoder and / or the radial part of the disc element further hinders the ingress of dirt and water into the seal.

[0013] Preferably, the axial part of the disc element has a rubber coating on the side facing away from the radial part, which extends radially along the end face of the axial part and at least partially covers the inner surface of the axial part. This rubber coating could be used as a final barrier, thus further preventing the ingress of dirt and water.

[0014] Preferably, the rubber lining on the inner surface of the axial part of the disc element is designed as a labyrinth seal.

[0015] A labyrinth seal is a seal that is typically formed by interlocking several sealing areas or lips, whereby the sealing lips are non-contacting. The non-contact sealing lips further reduce the friction of the seal.

[0016] In one embodiment, the outer ring has a recess on the side facing the disk element. A radial extension of the disk element or the encoder can, for example, extend into the area of ​​the recess, thus generating a labyrinth seal or pre-seal.

[0017] Preferably, the solid rubber lining has projections in the area of ​​the axial part of the sealing element and / or in the area of ​​the axial part of the disc element. These projections can be a single projection or multiple projections. The projections can extend radially towards the outer ring or inner ring, or the wheel hub. These projections further optimize the seal at this point, effectively preventing corrosion penetration.

[0018] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment 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 sealing device according to the state of the art Fig. 2 a section of a sealing device according to a first embodiment of the invention Fig. 3 a section of a sealing device according to a second embodiment of the invention Fig. 4 a section of a sealing device according to a third embodiment of the invention Fig. 5 a section of a sealing device according to a fourth embodiment of the invention Fig. 6 a section of a sealing device according to a fifth embodiment of the invention Fig. 7 a section of a sealing device according to a sixth embodiment of the invention Fig. 8 a section of a sealing device according to a seventh embodiment of the invention Fig. 9 a section of a sealing device according to an eighth embodiment of the invention Fig. 10 a section of a sealing device according to a ninth embodiment of the invention Fig. 10a a detailed view D from the section of the ninth embodiment according to Fig. 10 Fig. 11 a section of a sealing device according to a tenth embodiment of the invention

[0019] Fig. Figure 1 shows a section of a sealing device 4 of a wheel bearing unit 1 according to the known prior art. The sealing device 4 is fixed radially between an outer ring 2 and an inner ring 3 or a wheel hub (not shown). The sealing device 4 typically comprises a sealing element 5 and a disc element 6, wherein the sealing element 5 is attached to the outer ring 2 via an interference fit and the disc element 6 is attached to the inner ring 3 or the wheel hub via an interference fit. The interference fit creates a static sealing surface. The outer ring 2 and the inner ring 3 or the wheel hub are typically ground in the area of ​​the interference fit of the sealing element 5 and the disc element 6.

[0020] Fig. Figure 2 shows an embodiment of a sealing device 4 according to the invention, which also comprises a sealing element 5 and a disc element 6, which are attached to the outer ring 2 and inner ring 3 via press fits. The sealing element 5 has an axial part 5a and an adjoining radial part 5b. An elastic sealing element in the form of an elastomer is provided on the sealing element 5. In the illustrated embodiment, the sealing element 5 is completely enclosed by the elastic sealing element. To prevent corrosion ingress in the area of ​​the static sealing seat between the axial part 5a of the sealing element and the outer ring 2, the axial part 5a is completely rubberized on the side facing the outer ring 2. In this way, the ingress of dirt and water can be effectively prevented.At the same time, the need for complex grinding of the outer ring surface in this area can be avoided, making the seal cheaper and more durable.

[0021] The elastic sealing element on the sealing element 5 has a sealing lip extending in the axial direction A, which contacts the disc element 6. The disc element 6 has an axial part 6a and an adjoining radial part 6b. In particular, the sealing lip contacts the disc element 6 at the radial part 6b. The axial part 6a of the disc element 6 is completely rubberized on the side facing the inner ring 2. Furthermore, the disc element 6 has an encoder 9. The encoder 9 consists in particular of a radial part 9a, which extends along the radial part 6b of the disc element, and an axial part 9b, which adjoins the end of the radial part 9a of the encoder 9 facing the outer ring 2 and extends in the axial direction A towards the sealing element 5 without contacting it.Instead of the axial part 9b of the encoder 9, a second axial part of the disc element can also be provided, which connects to the radial part 6b of the disc element 2 and extends axially in direction A towards the sealing element 5 without contacting it. By providing an axial part – either through the encoder 9 or through the disc element 5 itself – an entry gap S is generated, which runs axially between the sealing element 5 and the axial part of the encoder or the disc element 6, respectively, and makes it more difficult for dirt and water to penetrate the sealing device 4. In the embodiment shown, the ring surfaces of the outer ring 2 and inner ring 3 are only pre-turned, not ground, which reduces the cost of the wheel bearing unit 1. Both the sealing element 5 and the disc element 6 have fully rubberized seats.

[0022] Fig. Figure 3 shows an embodiment that is essentially the same as the one made up of Fig. 2. The difference lies in the formation of a pre-labyrinth in the area of ​​the inlet gap S between sealing element 5 and disc element 6 or encoder 9. The encoder material is extended at its radial part 9a beyond the length of the radial part 6b of the disc element 6 in the direction of the outer ring 2. This radial extension 9d on the encoder is connected to the axial part 9b of the encoder 9 via an inclined surface 9c. Due to the inclined surface 9c, any dirt particles that have already entered can be more easily ejected from the sealing device 4 when the seal rotates. The inlet gap S thus has a first axial gap between the outer ring and the extension of the encoder 9d, a subsequent second gap between the inclined surface on the encoder 9c and the sealing element 5, and a subsequent third gap between the sealing element 5 and the axial part 9b of the encoder 9.

[0023] Fig. Figure 4 shows an almost identical structure of the sealing device 4. Fig. 3, with the difference that in this embodiment the extension on the encoder 9d extends radially R to the level of the outer ring 2. In particular, the encoder 9 almost completely covers the outer ring 2 in the radial direction. This generates an extended input gap S in the axial direction A between the outer ring 2 and the encoder 9.

[0024] Fig. Figure 5 shows an embodiment of a sealing device 4, which is essentially based on the structure of the sealing device made of Fig. 4 corresponds. Here too, an extension is provided on the encoder 9d in the radial direction R at the level of the outer ring 2. However, here the radial part 6b of the disk element is also extended in the radial direction R up to the level of the outer ring 2, which allows this area to be designed more stably.

[0025] Fig. Figure 6 shows an embodiment of a sealing device 4, which is essentially based on the structure of the sealing device made of Fig. 3. Here, however, not only is the part of the axial part 6a of the disc element 6 facing the inner ring 3 provided with a rubber coating 7. The axial part 6a of the disc element 6 has a rubber coating 7a on the side facing away from the radial part 6b, which extends in radial direction R on the end face of the axial part 6a and at least partially rubberizes the inner surface 6c of the axial part. The rubber coating on the inner surface 6c, together with the elastic sealing body of the sealing element 5, forms a gap that can serve as a labyrinth seal 8a. The rubber coating on the inner surface 6c has an inclination, and the elastic sealing body of the sealing element 5 has a correspondingly complementary inclination in the area of ​​the labyrinth seal 8a.

[0026] In Fig. 7 shows a variant that is in Fig. 6 essentially corresponds to. Here, it is shown how the labyrinth seal 8a can be formed on the inner surface 6c of the disc element. Here, the entire inner surface 6c on the axial part 6a of the disc element 6 is rubberized. A first part of the rubber coating 7a has a radial height that is greater than the radial height of a second part of the rubber coating. Through the taller part of the rubber coating 7a, a labyrinth seal 8a in the form of a gap S can again be generated.

[0027] Fig. Figure 8 shows another variant of a sealing device 4 with a labyrinth seal 8a between the axial part 6a of the disc element 6 and the elastic sealing body of the sealing element 5. The construction of the remaining sealing components essentially corresponds to those of Fig. 6. In this embodiment, the rubber lining 7a of the inner surface 6c of the disc element 6 has at least one, preferably several, sealing lips 7b which, together with several sealing lips 5c of the elastic sealing body, form gaps and thus constitute a labyrinth seal 8a. Preferably, the sealing lips 5c of the elastic sealing body and of the rubber lining 7b are non-contacting.

[0028] In Fig. 9 shows another variant, which is essentially the same as the variant shown. Fig. 8 corresponds to this. Here, two sealing lips 7b are provided on the rubber lining 7a, which, together with two sealing lips 5c of the elastic sealing body, form a labyrinth seal 8a. For this purpose, one sealing lip 7b of the rubber lining 7a projects radially and without contact into a groove that is formed between two sealing lips 5c of the elastic sealing body. This creates a gap that makes it difficult for particles to enter the seal.

[0029] In Fig. Figure 10 shows a further embodiment according to the invention. As in previous embodiments, the sealing element 5 is pressed into the outer ring 2 and has a complete rubber coating 7 on its axial part 5a on the side facing the outer ring 2. An elastic sealing body is provided on the sealing element 5, which has several sealing lips, at least one of which is in contact with the disc element 6. As in previous embodiments, the disc element 5 also has a complete rubber coating 7 on the side of its axial part 6a facing the inner ring, which seamlessly transitions into the encoder 9 in the radial direction R. In this embodiment as well, the encoder 9 extends radially R 9d into a recess 10 of the outer ring 2. The encoder 9 thus overlaps the outer ring 2 at least partially in the radial direction R.The encoder 9 also has an axial part 9b that extends from the radial part 9a of the encoder in axial direction A and forms a labyrinth seal 8 together with the outer ring 2. Alternatively, instead of the axial part 9b of the encoder, an axial extension of the disk element 6 can also form a labyrinth seal 8 with the outer ring 2. In this case, the disk element 6 is C-shaped.

[0030] As in Fig. As shown in detail in Figure 10a D, the rubber coating 7 on the surface of the sealing element 5 facing the outer ring 2 and / or on the surface of the disc element 6 facing the inner ring 3 is formed with at least one, preferably several, projections 11. These projections help to prevent corrosion from creeping underneath the seal.

[0031] Fig. Figure 11 shows a further embodiment of the sealing device 4, which is essentially the same as the structure of the sealing device 4 made of Fig.10. However, here the recess 10 on the outer ring 2 is significantly longer in the axial direction A. The recess 10 extends beyond the area in which the sealing element 5 is pressed in with its axial part 5a. The encoder 9 has a radial extension 9d and an axial part 9b that extends towards the sealing element 5. Several non-contacting sealing lips 5c are provided on the sealing element 5, extending in the axial direction A towards the disk element 6 or the encoder 9. Reference symbol list 1 wheel bearing unit 2 outer ring 3 inner ring 4 Sealing device 5 Sealing element 5a Axial part of the sealing element 5b Radial part of the sealing element 5c Sealing lips 6 disc elements 6a Axial part of the disk element 6b Radial part of the disk element 6c Inner surface 7 Rubber coating 7a Rubber coating 7b Sealing lips 8 Labyrinth seal 8a Labyrinth seal 9 encoders 9a Radial part of the encoder 9b Axial part of the encoder 9c Inclined surface of the encoder 9d Radial extension at the encoder 10 Exclusion 11 protrusions S entrance gap A Axial direction 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 2016 125 093 A1

[0002]

Claims

[1] Wheel bearing unit (1) for a motor vehicle, comprising an outer ring (2) and an inner ring (3) fixed on a wheel hub, wherein a sealing device (4) is provided between the outer ring (2) and the wheel hub or the inner ring (3), wherein the sealing device (4) comprises at least a sealing element (5) and a disc element (6), wherein the sealing element (5) is attached to the outer ring (2) and the disc element (6) is attached to the wheel hub or the inner ring (3), wherein the disc element (6) has an axial part (6a) and a radial part (6b), and wherein the sealing element (5) has an axial part (5a) and a radial part (5b), characterized by , that the axial part (6a) of the disc element (6) is completely rubberized (7) on the surface facing the inner ring (3) or the wheel hub and / or that the axial part (5a) of the sealing element (5) is completely rubberized (7) on the surface facing the outer ring (2). [2] Wheel bearing unit (1) according to claim 1, characterized by , that the contact surface of the outer ring (2) to the axial part (5a) of the sealing element (5) and / or the contact surface of the inner ring (3) or the wheel hub to the axial part (6a) of the disc element (6) is unground. [3] Wheel bearing unit (1) according to claim 1 or 2, characterized by , that the contact surface of the outer ring (2) to the axial part (5a) of the sealing element (5) and / or the contact surface of the inner ring (3) or the wheel hub to the axial part (6a) of the disc element (6) has a roughness (roughness depth Rz) of 6.3 ≤ Rz ≤ 25 µm. [4] Wheel bearing unit (1) according to any one of the preceding claims, characterized by , that an inlet gap (S) is provided between sealing element (5) and disc element (6), in which a labyrinth seal (8) is formed. [5] Wheel bearing unit (1) according to any one of the preceding claims, characterized by, that the disk element (6) has an encoder (9) on its radial part (6b) which extends in radial direction (R) at least to the level of the outer ring (2). [6] Wheel bearing unit (1) according to claim 5, characterized by , that encoder (9) and the radial part (6b) of the disk element (6) extend in radial direction (R) at least to the level of the outer ring (2). [7] Wheel bearing unit (1) according to any one of the preceding claims, characterized by , that the axial part (6a) of the disc element (6) has a rubber coating (7a) on the side facing away from the radial part (6b), which extends in radial direction (R) on the end face of the axial part (6a) and at least partially rubberizes the inner surface (6c) of the axial part (6a). [8] Wheel bearing unit (1) according to claim 7, characterized by , that the rubber coating () on the inner surface (6c) of the axial part (6a) of the disc element (6) forms a labyrinth seal (8a). [9] Wheel bearing unit (1) according to any one of the preceding claims, characterized by , that the outer ring (2) has a recess (10) on the side facing the disk element (6). [10] Wheel bearing unit (1) according to any one of the preceding claims, characterized by , that the rubber coating (7) has projections (11) in the area of ​​the axial part (5a) of the sealing element (5) and / or in the area of ​​the axial part (6a) of the disc element (6).

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