SEALING ARRANGEMENT FOR WHEEL BEARINGS, AND WHEEL BEARING UNIT COMPRISING A SEALING ARRANGEMENT

Abstract

A sealing arrangement for a wheel bearing includes a carrier element connectable to a first bearing part of the wheel bearing, a resilient sealing element, and a counterflow plate connectable to a second bearing part of the wheel bearing. The resilient sealing element includes a resilient main body arranged on the carrier element, first and second axial sealing lips extending away from the resilient main body, and a radial sealing lip extending away from the resilient main body. The counterflow plate is arranged with one side facing the carrier element such that the first and second axial sealing lips, and the radial sealing lip, are in sliding contact with the counterflow plate. The first axial sealing lip, second axial sealing lip, and radial sealing lip rest against the counterflow plate with respective contact pressures.

Claims

1. A sealing arrangement for a wheel bearing, comprising: a carrier element which can be connected to a first bearing part of the wheel bearing; a resilient sealing element which comprises a resilient main body that is arranged on the carrier element, wherein the resilient sealing element also comprises at least a first axial sealing lip and a second axial sealing lip and at least one radial sealing lip that extend away from the resilient main body; and a counterflow plate which can be connected to a second bearing part and is arranged with one side facing the carrier element such that the first axial sealing lip, the second axial sealing lip and the radial sealing lip are in sliding contact with the counterflow plate, wherein: the first axial sealing lip is designed in such a way that it rests against the counterflow plate with a first contact pressure (F.sub.1); the second axial sealing lip is designed such that it rests against the counterflow plate with a second contact pressure (F.sub.2); the radial sealing lip is designed such that it rests against the counterflow plate with a third contact pressure (F.sub.3); and the first, second, and third contact pressures (F.sub.1, F.sub.2, F.sub.3) are defined as a function of a predefined force ratio.

2. The sealing arrangement according to claim 1, wherein the predefined force ratio is defined by the following equations:
the first contact pressure (F.sub.1)=the second contact pressure (F.sub.2)±0.9 N; and
the third contact pressure (F.sub.3)=0.5*(the first contact pressure (F.sub.1))±0.9 N.

3. The sealing arrangement according to claim 1, wherein the resilient main body of the resilient sealing element is arranged, at least in a region of the first and second axial sealing lips, in an axial direction (A) at a first axial distance (l.sub.A1) from the counterflow plate.

4. The sealing arrangement according to claim 3, wherein the first axial sealing lip and the second axial sealing lip have a first radial distance (l.sub.R1) from one another in a radial direction (R) on the counterflow plate and have a second radial distance (l.sub.R2) from each other on the carrier element, wherein the first radial distance (l.sub.R1) and the second radial distance (l.sub.R2) are defined as a function of the first axial distance (l.sub.A1).

5. The sealing arrangement according to claim 4, wherein the first axial sealing lip on the resilient main body has a first radial thickness (d.sub.R1) in the radial direction (R), and the second axial sealing lip on the resilient main body has a second radial thickness (d.sub.R2) in the radial direction (R), wherein the first radial thickness (d.sub.R1) and the second radial thickness (d.sub.R2) are defined as a function of the second radial distance (l.sub.R2).

6. The sealing arrangement according to claim 1, wherein the first axial sealing lip and the second axial sealing lip are arranged obliquely with respect to an angle in relation to an axis of rotation of the wheel bearing, wherein a diameter of the axial sealing lips, viewed in an axial direction (A), increases from the resilient main body to the counterflow plate.

7. The sealing arrangement according to claim 6, wherein an inner peripheral surface of the first axial sealing lip is arranged at a first inner peripheral surface angle (α.sub.1) to the axis of rotation and an outer peripheral surface of the first axial sealing lip is arranged at a first outer peripheral surface angle (α.sub.2) to the axis of rotation, wherein the first outer peripheral surface angle (α.sub.2) is defined as a function of the first inner peripheral surface angle (α.sub.1).

8. The sealing arrangement according to claim 6, wherein an inner peripheral surface of the second axial sealing lip is arranged at a second inner peripheral surface angle (β.sub.1) to the axis of rotation and an outer peripheral surface of the second axial sealing lip is arranged at a second outer peripheral surface angle (β.sub.2) to the axis of rotation, wherein the second outer peripheral surface angle (β.sub.2) is defined as a function of the second inner peripheral surface angle (β.sub.1).

9. A use of the sealing arrangement according to claim 1 for sealing a wheel bearing.

10. A wheel bearing unit for a motor vehicle, comprising: a wheel bearing which is designed as a roller bearing, and a sealing arrangement according to claim 1, which is arranged adjacent to at least one axial side of the wheel bearing.

11. A sealing arrangement for a wheel bearing, comprising: a carrier element connectable to a first bearing part of the wheel bearing; a resilient sealing element comprising: a resilient main body arranged on the carrier element; a first axial sealing lip extending away from the resilient main body; a second axial sealing lip extending away from the resilient main body; and a radial sealing lip extending away from the resilient main body, and a counterflow plate connectable to a second bearing part of the wheel bearing, the counterflow plate being arranged with one side facing the carrier element such that the first axial sealing lip, the second axial sealing lip and the radial sealing lip are in sliding contact with the counterflow plate, wherein: the first axial sealing lip rests against the counterflow plate with a first contact pressure; the second axial sealing lip rests against the counterflow plate with a second contact pressure; the first contact pressure is equal to the second contact pressure ±0.9 N; the radial sealing lip rests against the counterflow plate with a third contact pressure; and the third contact pressure is half of the first contact pressure ±0.9 N.

12. The sealing arrangement of claim 11, wherein a region of the resilient main body radially between the first axial sealing lip and the second axial sealing lip is arranged at a first axial distance from the counterflow plate.

13. The sealing arrangement of claim 12, wherein: the first axial sealing lip is disposed at a first radial distance from the second axial sealing lip when measured on the counterflow plate; the first radial distance is between 1.03 and 1.24 times the first axial distance; the first axial sealing lip is disposed at a second radial distance from the second axial sealing lip when measured on the carrier element; and the second radial distance is between 1.27 and 1.59 times the first axial distance.

14. The sealing arrangement of claim 13, wherein: the first axial sealing lip comprises a first radial thickness measured at the resilient main body; the first radial thickness is between 0.38 and 0.5 times the second radial distance; the second axial sealing lip comprises a second radial thickness measured at the resilient main body; and the second radial thickness is between 0.4 and 0.5 times the second radial distance.

15. The sealing arrangement of claim 12, wherein: the first axial sealing lip is disposed at a first radial distance from the second axial sealing lip when measured on the counterflow plate; the first axial sealing lip is disposed at a second radial distance from the second axial sealing lip when measured on the carrier element; and the second radial distance is between 0.629 and 0.787 times the first radial distance.

16. The sealing arrangement of claim 15, wherein: the first axial sealing lip comprises a first radial thickness measured at the resilient main body; the first radial thickness is between 0.38 and 0.5 times the second radial distance; the second axial sealing lip comprises a second radial thickness measured at the resilient main body; and the second radial thickness is between 0.4 and 0.5 times the second radial distance.

17. The sealing arrangement of claim 11, wherein: a first diameter of the first axial sealing lip increases as the first axial sealing lip extends from the resilient main body towards the counterflow plate; and a second diameter of the second axial sealing lip increases as the second axial sealing lip extends from the resilient main body towards the counterflow plate.

18. The sealing arrangement of claim 17, wherein: the first axial sealing lip comprises: a first inner peripheral surface arranged at a first inner peripheral surface angle measured relative to an axis of rotation of the sealing arrangement; and a first outer peripheral surface arranged at a first outer peripheral surface angle, different than the first inner peripheral surface angle, measured relative to the axis of rotation.

19. The sealing arrangement of claim 17, wherein: the second axial sealing lip comprises: a second inner peripheral surface arranged at a second inner peripheral surface angle measured relative to an axis of rotation of the sealing arrangement; and a second outer peripheral surface arranged at a second outer peripheral surface angle, different than the second inner peripheral surface angle, measured relative to the axis of rotation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other measures improving the invention are described in more detail below together with the description of a preferred embodiment of the invention based on the figures. In the figures:

[0027] FIG. 1 shows a schematic longitudinal section of a wheel-flange-side sealing arrangement according to one embodiment of the disclosure;

[0028] FIG. 2 shows a schematic longitudinal section of a vehicle-side sealing arrangement according to one embodiment of the disclosure; and

[0029] FIG. 3 shows a schematic longitudinal section of a wheel-flange-side sealing arrangement according to a further embodiment of the disclosure.

[0030] The figures are only schematic in nature and serve only for understanding of the disclosure. The same elements are provided with the same reference signs.

[0031] FIG. 1 shows a sealing arrangement 1, which is arranged in the axial direction A between a wheel bearing 2 and a wheel bearing flange 3, wherein only sections of both the wheel bearing 2 and the wheel bearing flange 3 are shown. The wheel bearing 2 is designed as a roller bearing with rolling elements 4, which are held by a cage 5 in rolling raceways of bearing rings 6 holding the rolling elements 4.

[0032] The sealing arrangement 1 has a carrier element 7 which is fixed to one of the bearing rings 6 with a fastening section 8. A resilient sealing element 9 is arranged on the carrier element 7 and has a resilient main body 10 from which a first axial sealing lip 11, a second axial sealing lip 12 and a radial sealing lip 13 extend away. Furthermore, the sealing arrangement 1 has a counterflow plate 14 which is arranged facing the carrier element 7 such that it is in sliding contact with the axial sealing lips 11, 12 and the radial sealing lip 13. The counterflow plate 14 is fixed with a fastening section 15 to the wheel bearing flange 3 which is formed integrally with the other of the bearing rings 6 (not shown here). In addition, a resilient sealing element 16 is arranged on the counterflow plate 14 in the region of the fastening section 15 and seals a coupling point between the fastening section 15 and the wheel bearing flange 3.

[0033] The sliding contact is graphically illustrated by the overlapping representation of the sealing lips 11, 12, 13 with the counterflow plate 14. In practice, the sealing lips 11, 12, 13 do not overlap with the counterflow plate 14, but are in contact with the counterflow plate 14 in such a way that during a rotational movement of the wheel bearing flange 3, and thus of the counterflow plate 14, there is sliding contact between the sealing lips 11, 12, 13 and the counterflow plate 14. The sliding contact is individual for each of the sealing lips 11, 12, 13 and is defined in that the sealing lips 11, 12, 13 each rest against the counterflow plate 14 with a predetermined contact pressure F.

[0034] The first axial sealing lip 11 rests against the counterflow plate 14 with a first contact pressure F.sub.1 and the second axial sealing lip 12 with a second contact pressure F.sub.2. The radial sealing lip 13 rests against the counterflow plate 14 with a third contact pressure F.sub.3. The first and the second contact pressures F.sub.1, F.sub.2 are applied in the axial direction A and the third contact pressure F.sub.3 is applied in the radial direction R.

[0035] The contact pressures F.sub.1, F.sub.2 and F.sub.3 are in a predetermined force ratio to one another, which defines the contact pressures F.sub.1, F.sub.2, F.sub.3 as functions of one another as follows:

F.sub.1=F.sub.2±0.9 N  (1)

and

F.sub.3=0.5*F.sub.1±0.9 N  (2)

The specification off ±0.9 N indicates a tolerance range for the calculation of the forces.

[0036] The counterflow plate 14 is arranged in the axial direction A at a first axial distance l.sub.A1 from the carrier element 7 with the resilient main body 10, so that a free space, i.e. a sealing space 17, is formed. The axial sealing lips 11, 12 substantially extend obliquely in the axial direction A through the sealing space 17 to the counterflow plate 14 and are spaced apart from one another in the radial direction R. The first axial sealing lip 11 is arranged further inward than the second axial sealing lip 12, viewed in the radial direction R.

[0037] The distance between the two axial sealing lips 11, 12 is not constant over their length, that is, a first radial distance l.sub.R1 between the first axial sealing lip 11 and the second axial sealing lip 12 on the counterflow plate 14 differs from a second radial distance l.sub.R2 between the first axial sealing lip 11 and the second axial sealing lip 12 on the carrier element 7. Both the first radial distance l.sub.R1 and the second radial distance l.sub.R2 are defined as a function of the first axial distance l.sub.A1. In the embodiment shown in this figure, the first axial distance l.sub.A1 is, for example, greater than or equal to 1.7 mm and the first radial distance l.sub.R1 and the second radial distance l.sub.R2 are defined, for example, as follows:

l.sub.R1=l.sub.A1*1.24  (3)

and

l.sub.R2=l.sub.A1/1.27  (4)

[0038] In addition, the first axial sealing lip 11 on the carrier element 7 has a first radial thickness d.sub.R1, and the second axial sealing lip 12 on the carrier element 7 has a second radial thickness d.sub.R2. The two radial thicknesses d.sub.R1, d.sub.R2 are in turn defined as a function of the second radial distance l.sub.R2 and are therefore also defined as a function of the first axial distance l.sub.A1:

d.sub.R1=l.sub.R2*0.38=(l.sub.A1/1.27)*0.38  (5)

and

d.sub.R2=l.sub.R2*0.4=(l.sub.A1/1.27)*0.4  (6)

[0039] Furthermore, the thickness of the axial sealing lips 11, 12 also changes over their direction of extension. This change in thickness is indicated by a ratio between an inner peripheral surface angle and an outer peripheral surface angle of the respective axial sealing lip 11, 12. An angle between an inner peripheral surface of the respective axial sealing lip 11, 12 and an axis of rotation (not shown) of the sealing arrangement 1 is referred to as an inner peripheral surface angle, and an angle between an outer peripheral surface of the respective axial sealing lip 11, 12 and the axis of rotation of the sealing arrangement 1 is referred to as an outer peripheral surface angle. The outer peripheral surface angle is a function of the inner peripheral surface angle.

[0040] In the embodiment shown in FIG. 1, a first inner peripheral surface angle α.sub.1 of the first axial sealing lip 11 is between 33° and 36°. A second inner peripheral surface angle β.sub.1 of the second axial sealing lip 12 is between 36° and 39°. A first outer peripheral surface angle α.sub.2 and a second outer peripheral surface angle β.sub.2 are then defined as follows:

α.sub.2=(α.sub.1−0.553°)±1°  (7)

and

β.sub.2=(β.sub.1−0.342°)±1°  (8)

The specification ±1° indicates a tolerance range for the dimensioning of the angle.

[0041] It can thus be seen that the sealing arrangement 1 is designed firstly by means of the contact pressures of the sealing lips 11, 12, 13 on the counterflow plate 14 and secondly as a function of the first axial distance l.sub.A1. The first axial distance l.sub.A1 is directly related to the installation space available for the sealing arrangement 1. This means that the sealing arrangement 1 is designed essentially as a function of the available installation space and the necessary first contact pressure F.sub.1.

[0042] FIG. 2 shows the sealing arrangement 1, which is arranged in the axial direction A between a wheel bearing 2 and a chassis 18, wherein only sections of both the wheel bearing 2 and the chassis 18 are shown. The structure of the sealing arrangement 1 is very similar to that of the embodiment shown in FIG. 1, for which reason only the differences are discussed below. Due to a different installation position of the sealing arrangement 1, which is arranged mirror-inverted compared to FIG. 1, the first axial distance l.sub.A1 is greater than or equal to 1.95 mm. This results in the following length and angle ratios for the embodiment shown here:

l.sub.R1=l.sub.A1*1.03

l.sub.R2=l.sub.A1/1.59

d.sub.R1=l.sub.R2*0.40=(l.sub.A1/1.59)*0.40

d.sub.R2=l.sub.R2*0.45=(l.sub.A1/1.59)*0.45

α.sub.1=33° to 36° and α.sub.2=(α.sub.1−0.58°)±1°

β.sub.1=36° to 39° and β.sub.2=(β.sub.1−0.335)°±1°

The force ratio of the contact pressures F.sub.1, F.sub.2 and F.sub.3 corresponds to the force ratio described with reference to FIG. 1.

[0043] FIG. 3 shows a further embodiment of the sealing arrangement 1 according to the disclosure. It can be seen that the carrier element 7 is designed slightly differently and the sealing arrangement 1 is shown alone, without reference to adjacent elements. In this embodiment too, the force ratio of the contact pressures F.sub.1, F.sub.2 and F.sub.3 corresponds to the force ratio described with reference to FIG. 1.

[0044] In the embodiment shown here, the first axial distance l.sub.A1 is greater than or equal to 2 mm. This results in the following length and angle ratios:

l.sub.R1=l.sub.A1*1.15

l.sub.R2=l.sub.A1/1.45

d.sub.R1=l.sub.R2*0.50=(l.sub.A1/1.45)*0.50

d.sub.R2=l.sub.R2*0.50=(l.sub.A1/1.45)*0.50

α.sub.1=25° to 28° and α.sub.2=(α.sub.1+4.7)°±1°

β.sub.1=30° to 33° and β.sub.2=(β.sub.1+5.1°)±1°

[0045] In addition, the sealing arrangement 1 shown here also has a third axial sealing lip 19 which does not extend as far as the counterflow plate 14 and is arranged outside of the second axial sealing lip 12 when viewed in the radial direction R. The third axial sealing lip 19 serves as a pre-seal 20 and forms a labyrinth seal in the sealing space 17, which is intended to direct particles penetrating from the outside, such as dirt, dirty water, dust, etc., back to the outside. For this purpose, the third axial sealing lip 19 is arranged obliquely outwards at an angle γ relative to the axis of rotation of the sealing arrangement 1, wherein the angle γ is approximately 30° here, for example. The pre-seal 20 is intended to protect the first and the second axial sealing lip 11, 12 from the penetrating particles, whereby the service life of the sealing arrangement 1 can be further increased.

[0046] In addition, an inner diameter D.sub.I of the counterflow plate 14 is indicated in FIG. 3, which is 80 mm here, for example.

REFERENCE NUMERALS

[0047] 1 Sealing arrangement [0048] 2 Wheel bearing [0049] 3 Wheel bearing flange [0050] 4 Rolling element [0051] 5 Cage [0052] 6 Bearing ring [0053] 7 Carrier element [0054] 8 Fastening section [0055] 9 Resilient sealing element [0056] 10 Resilient main body [0057] 11 First axial sealing lip [0058] 12 Second axial sealing lip [0059] 13 Radial sealing lip [0060] 14 Counterflow plate [0061] 15 Fastening section [0062] 16 Sealing element [0063] 17 Sealing space [0064] 18 Chassis [0065] 19 Third axial sealing lip [0066] 20 Pre-seal [0067] F, F.sub.1, F.sub.2, F.sub.3 Contact pressure [0068] l.sub.A1 Axial distance [0069] l.sub.R1, l.sub.R2 Radial distance [0070] d.sub.R1, d.sub.R2 Radial thickness [0071] D.sub.I Inner diameter [0072] α.sub.1, β.sub.1 Inner peripheral surface angle [0073] α.sub.2, β.sub.2 Outer peripheral surface angle [0074] γ Angle [0075] R Radial direction [0076] A Axial direction