WHEEL BEARING UNIT

Abstract

A wheel bearing unit includes an outer ring, a first inner ring with a first axial end face, first rolling elements arranged between the outer ring and the first inner ring, a second inner ring with a second axial end face, facing the first axial end face, second rolling elements arranged between the outer ring and the second inner ring, and a sealing device for sealing an interface of the first inner ring and the second inner ring. The sealing device includes an annular retaining element and a sealing element provided on the annular retaining element. The sealing element is a sealing ring that includes first and second contact points contacting the annular retaining element, a third contact point contacting the first inner ring, and a fourth contact point contacting the second inner ring. At least one of the contact points has a flat face.

Claims

1.-9. (canceled)

10. A wheel bearing unit comprising: an outer ring; a first inner ring comprising a first axial end face; first rolling elements arranged between the outer ring and the first inner ring and guided in a first cage; a second inner ring comprising a second axial end face, facing the first axial end face; second rolling elements arranged between the outer ring and the second inner ring and guided in a second cage; and a sealing device for sealing an interface of the first inner ring and the second inner ring, the sealing device comprising: an annular retaining element; and a sealing element provided on the annular retaining element, wherein: the sealing element is a sealing ring comprising: first and second contact points contacting the annular retaining element; a third contact point contacting the first inner ring; and a fourth contact point contacting the second inner ring; and at least one of the contact points comprises a flat face.

11. The wheel bearing unit of claim 10, wherein: the sealing element comprises a lead-in chamfer; and the lead-in chamfer is formed from a first angle and a second angle.

12. The wheel bearing unit of claim 10, wherein the sealing element comprises: a material comprising a hardness; and a minimum contour thickness depending on the hardness.

13. The wheel bearing unit of claim 10, wherein: the first inner ring and the second inner ring comprise respective depressions in a region of the first axial end face and the second axial end face; the respective depressions form a common annular groove; and the sealing device is arranged in the common annular groove.

14. The wheel bearing unit of claim 13, wherein the annular retaining element is designed in a U-shape comprising: a circumferential web; and two side rings connected by the circumferential web.

15. The wheel bearing unit of claim 14, wherein one or both of the two side rings forms a positioning aid that is centered and positioned on an edge of the common annular groove.

16. The wheel bearing unit of claim 14, wherein one or both of the two side rings comprises an interruption.

17. The wheel bearing unit of claim 10, wherein the annular retaining element is designed in a U-shape comprising: a circumferential web; and two side rings connected by the circumferential web.

18. The wheel bearing unit of claim 10, wherein the sealing ring is made of a rubber elastic material.

19. The wheel bearing unit of claim 10, wherein the annular retaining element is made of a plastic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Two exemplary embodiments of the disclosure are shown below with reference to the figures. In the figures:

[0026] FIG. 1 shows a longitudinal section through a wheel bearing unit according to the disclosure,

[0027] FIG. 2 shows a longitudinal section through a sealing device of the wheel bearing unit according to the disclosure.

[0028] FIG. 3 shows a longitudinal section through a sealing device of the wheel bearing unit according to the disclosure,

[0029] FIG. 4 shows an enlarged view of the sealing device shown in FIG. 3,

[0030] FIG. 5 shows a longitudinal section through a sealing device of the wheel bearing unit according to the disclosure,

[0031] FIG. 6a shows an illustration of the change in position of the sealing device of the wheel bearing unit according to the disclosure,

[0032] FIG. 6b shows an illustration of the change in position of the sealing device of a wheel bearing unit known from the prior art, and

[0033] FIG. 7 shows a perspective view of the sealing device of the wheel bearing unit according to the disclosure.

DETAILED DESCRIPTION

[0034] FIG. 1 shows a longitudinal section through a wheel bearing unit 1 according to the disclosure. The wheel bearing unit is designed as a double-row tapered roller bearing 2. The tapered roller bearing 2 has an inner ring 3 and an outer ring 4. Tapered rollers 5 are arranged between the running surfaces formed by the inner ring 3 and the outer ring 4, which roll on the running surfaces.

[0035] One end face 6 of each of the two inner rings 3 bears against the other and thus forms an interface 7. A sealing device 8 is provided to seal this interface 7. As can be seen from FIG. 1, the two inner rings 3 form an annular groove 9. This is formed by corresponding depressions in the two inner rings 3.

[0036] The sealing device 8 is formed by an annular retaining element 10, on which at least one sealing element 11 is provided. The sealing element is designed as a sealing ring 12. The sealing ring 12 is made of a rubber elastic material. For a more detailed explanation of the sealing element 11, reference is now made to FIGS. 2, 3 and 4. The sealing ring 12 has two contact points 13, 14, which contact the retaining element 10, and one contact point 15, 16, which contacts each inner ring 3. By means of this special design, the sealing ring 12 is pressed radially against the inner rings 3 during installation and radially tensioned accordingly. So, even if the inner rings 3 are displaced axially, the radial sealing or radial tensioning of the sealing element 11 remains unaffected.

[0037] At least one of the contact points 13, 14, 15, 16 is designed in such a way that it has a flat face X. This flat face increases the adhesion forces that occur in the region of the sealing device 8, which can increase the sealing performance. In the case of pointed surfaces of the sealing element 11 known from the prior art, an additional medium may be necessary to exert the required pressure on the seal. Another advantage of the embodiment according to the disclosure is that the contact points 13, 14, 15, 16 and their contact zones remain unchanged throughout the service life. Furthermore, the flat face prevents sealing elements 11 from folding over during the course of the service life.

[0038] The sealing element 11 has at least one lead-in chamfer formed from a first angle a and a second angle b. The size of the angle a, b generally depends on the lead-in chamfers of the surrounding components. The first angle is at least 15? and the second angle is designed to be somewhat steeper and is at least 20?. The lead-in chamfers allow the sealing element 11 to be simply pushed onto the inner ring 3.

[0039] As can also be seen from FIG. 5, the sealing element 11 has a minimum contour thickness y. The minimum contour thickness depends on the hardness of the material. To ensure that the sealing effect is not reduced, the minimum contour thickness must be selected in such a way that, in combination with the selected material hardness, it exerts sufficiently large contact forces of the sealing element 11 on the surrounding components to guarantee a sufficient sealing effect. The minimum contour thickness is also selected in such a way that, in the presence of media and possibly chemical surface stresses, as well as temperature stresses on the sealing element material, the basic sealing function continues to be provided by a sufficiently unimpaired core material.

[0040] FIGS. 6a and 6b show a change in position of the sealing device of the wheel bearing unit according to the disclosure as well as a wheel bearing unit known from the prior art. FIG. 6a shows the embodiment according to the disclosure and FIG. 6b uses a sealing element 22 from the prior art. As can be seen from FIG. 6a, the sealing effect of the sealing element 11 is independent of a change in position of the sealing element 11 during an axial movement L of the seal itself or of the inner ring 3. The contact points 13, 14, 15, 16 are designed as a flat face X and remain the same during any movement. In contrast, FIG. 6b shows that the contact points 23 are affected by an axial movement L of the sealing element 22. The pointed contact points 23 fold over during the axial movement L and the contact points are thus minimized after a change in position.

[0041] FIG. 7 shows a design of the sealing device 8. The retaining element 10 is designed in a U-shape and has two side rings 17, 18 which are connected by means of a circumferential web 19. This ensures a secure hold of the sealing element 11 in the retaining element 8.

[0042] As can also be seen, the side rings are designed in such a way that they have several interruptions 20, 21 distributed around the circumference. The side rings 17, 18 simultaneously form a positioning aid which is centered and positioned on an edge of the annular groove 9.

REFERENCE NUMERALS

[0043] 1 Wheel bearing unit [0044] 2 Tapered roller bearing [0045] 3 Inner ring [0046] 4 Outer ring [0047] 5 Tapered rollers [0048] 6 End face [0049] 7 Interface [0050] 8 Sealing device [0051] 9 Annular groove [0052] 10 Retaining element [0053] 11 Sealing element [0054] 12 Sealing ring [0055] 13 Contact point [0056] 14 Contact point [0057] 15 Contact point [0058] 16 Contact point [0059] 17 Side rings [0060] 18 Side rings [0061] 19 Web [0062] 20 Interruption [0063] 21 Interruption [0064] 22 Sealing element, prior art [0065] 23 Contact points [0066] X Flat face [0067] a First angle [0068] b Second angle [0069] y Minimum contour thickness [0070] L Axial movement