WHEEL BEARING UNIT FOR A VEHICLE

Description

[0001] The invention relates to a wheel bearing unit for a vehicle, in particular a wheel bearing unit with a tapered roller bearing for a commercial vehicle, such as a truck.

[0002] Wheel bearing units with pre-assembled, press-fit rolling bearing units for commercial vehicles are used when proper installation of a wheel bearing, which typically consists of at least two wheel bearing units, is not possible in a standard automotive workshop. A clean environment and numerous precautions are essential for proper installation of a wheel bearing. Contamination of the rolling chamber not only impairs its properties but also reduces its service life. For example, wheel bearing units are known to have rolling bearings with two inner rings that are closely spaced at their ends. If the interface between the two inner rings is not adequately sealed, lubricant can leak from the rolling bearing or foreign substances can enter the rolling chamber.In both cases, a deterioration of the properties and a reduction in the bearing lifespan of the rolling bearing can be expected.

[0003] For example, DE 10 2018 130 926 A1 discloses a wheel bearing unit with at least one outer ring and at least two inner rings. Two adjacent inner rings abut each other with their opposing axial end faces, and a sealing device is provided to seal this interface between the two inner rings. The sealing device is formed by an annular retaining element. At least one sealing element, designed as a sealing ring, is arranged on the retaining element. The sealing ring has at least two contact points that contact the retaining element and at least one contact point that contacts each inner ring. JP 6 039431 B2 discloses the features of the preamble of claim 1.

[0004] The object of the present invention is to further develop a wheel bearing unit, whereby the assembly of the wheel bearing unit and the positioning of the sealing element are to be improved.

[0005] These problems are solved by a wheel bearing unit with the features of claim 1. Preferred or advantageous embodiments of the invention will become apparent from the following description and the accompanying figures.

[0006] A wheel bearing unit according to the invention for a vehicle, in particular for a truck, comprises at least one outer ring and at least two inner rings, between which rolling elements guided in a respective cage are arranged, wherein two adjacent inner rings come into contact with each other at an interface with their mutually facing axial end faces, wherein a sealing device is provided for sealing the interface of the two inner rings, wherein the sealing device is formed by a retaining ring with at least one sealing element, wherein the retaining ring comprises several axially extending web segments, each of which has a radially extending projection, wherein at least one of the two adjacent inner rings has a recess in an outer circumferential surface for at least partially receiving the projection on the respective web segment.

[0007] In other words, the raised section on each rib segment of the retaining ring penetrates at least partially or completely radially into the recess on the inner ring. By penetrating, and in particular snapping, the raised sections into the recess, the retaining ring, with its at least one sealing element, is positioned and fixed axially. When the retaining ring is axially slid onto the inner rings, the rib segments spring outwards in a radial direction, while upon penetration of the raised sections into the recess, they compress radially inwards. The compression movement of the rib segments is elastic, with the dimensions and material selection of the rib segments being primarily responsible for their elasticity and stiffness. Preferably, the retaining ring and the rib segments are made of a polymer material. Preferably, the sealing element is designed as a sealing ring.Preferably, several sealing rings can be provided on the retaining ring. In particular, during assembly of the wheel bearing unit, the at least one sealing element is pressed radially against the inner rings by means of the retaining ring and thus radially clamped. This position is fixed by means of the web segments, which also simplify the assembly of the retaining ring.

[0008] The sealing device is preferably hermetically sealing and self-locking, preventing, with minimal effort, the ingress of foreign substances and / or the migration of lubricant via the adjacent end faces of the inner rings into or out of the space within the wheel bearing unit where the rolling elements are arranged. Preferably, the sealing device is arranged in a common annular groove of the inner rings, which is formed by recesses in the area of ​​the opposing end faces of the inner rings. Providing the sealing device allows for sufficient radial clamping of the sealing element. Furthermore, the recesses create edges on the respective inner ring, which can additionally serve for the alignment, centering, and positioning of the sealing device.

[0009] According to a preferred embodiment, the recess is formed as a circumferential groove in the outer circumferential surface of one of the two adjacent inner rings. Thus, a single recess accommodates all the protrusions. A groove-shaped recess can be formed particularly easily and cost-effectively in the outer circumferential surface of the inner ring, for example, by machining. In particular, the recess has a rectangular cross-section. Preferably, the edges of the recess are rounded.

[0010] According to a preferred embodiment, the web segments are formed integrally with the retaining ring and arranged uniformly around the circumference. Thus, the retaining ring and the web segments are monolithic. The uniform distribution of the web segments, and consequently the raised sections, ensures that the retaining ring is securely positioned and consistently held during operation of the wheel bearing unit.

[0011] According to the invention, the respective projection is formed integrally on a central section of the respective bridge segment, wherein a centering section is formed integrally on the central section and extends axially away from the retaining ring. Thus, the respective bridge segment is formed from a central section connected to the retaining ring and a centering section connected to the central section. Alternatively, the centering section can be omitted (not claimed). Preferably, the centering section borders directly on the projection in the axial direction. Preferably, the central section is at least 3.5 mm to 9.5 mm long to facilitate easy assembly and secure positioning. Preferably, the centering section is at least 0.1 mm to 5 mm long to further simplify assembly by enabling faster and better centering of the retaining ring on the inner ring.Therefore, the total axial length of each bridge segment is at least 3.5mm and at most 14.5mm without axial overlap with the retaining ring.

[0012] According to a preferred embodiment, each transition area between the retaining ring and the respective bridge segment has a rounded contour, wherein this rounded contour comprises at least 18% and at most 40% of the length of the central section of the respective bridge segment. In other words, the respective bridge segment is connected to the retaining ring via the respective transition area. The transition areas, in particular, control the stiffness of the bridge segments, whereby deformation enables the projections to be axially slid over the end face and outer circumferential surface of the inner ring and to engage in the recess. In particular, a transition area between the end face and outer circumferential surface of the inner ring is rounded or blunt, especially ramp-shaped, to simplify the sliding of the retaining ring.The transition area between the retaining ring and the respective web segment is part of the central section and extends over at least 18% and at most 40% of the axial length of the central section. For example, the rounded contour on the retaining ring is formed by a radius of at least 0.5 mm to 3 mm. This radius is specifically tailored to the material properties of the retaining ring to allow for the necessary deformation during assembly while still ensuring a sufficiently high radial force for the web segments to engage.

[0013] According to a preferred embodiment, the raised section has a rounded contour. For example, the raised section has a rectangular cross-section with rounded corners. Alternatively, the raised section is cylindrical in the circumferential direction with a semicircular cross-section or a rectangular cross-section with rounded corners. In particular, the raised section is hemispherical. The cross-sectional area of ​​the recess is substantially complementary to the cross-sectional area of ​​the raised section. Preferably, the recess is slightly larger than the raised section to facilitate easier insertion and engagement of the raised section. In particular, the recess has rounded corners for this purpose.In particular, these rounded corners, especially the upper edges of the groove-shaped recess, are geometrically designed in such a way that the protrusions are as difficult as possible to snap out of the recess under operating loads and that at least one sealing element remains axially positioned.

[0014] For example, the axial dimension of the raised section is at least 12% to at most 45% of the axial length of the central section of the respective web segment. This particularly promotes a secure axial hold in the recess. Preferably, the axial dimension of the raised section is at least 20% to at most 36% of the axial length of the central section of the respective web segment. In particular, the axial dimension of the raised section is at least 0.5 mm to at most 3.5 mm, preferably at least 1.5 mm to 2.5 mm.

[0015] According to a preferred embodiment, each web segment forms a first axial stop for the at least one sealing element, wherein the retaining ring has several stop elements as second axial stops for the at least one sealing element. Thus, the at least one sealing element is positioned axially between the web segments and stop elements. In particular, the web segments and stop elements are arranged alternately in the circumferential direction.

[0016] According to a preferred embodiment, the recess has a depth of at least 0.5% to at most 10% of the outer diameter of the respective inner ring. Thus, the recess extends radially into the outer circumferential surface of the inner ring by 0.5% to at most 10% of the outer diameter of the respective inner ring. This provides, in particular, sufficient radial space for the penetration of the raised section and secure axial retention of the raised section within the recess. Preferably, the recess has a depth of at least 1.5% to at most 7% of the outer diameter of the respective inner ring.

[0017] According to a preferred embodiment, the inner ring has an outer diameter of 59 mm to 140 mm, while the retaining ring has an outer diameter of 65 mm to 160 mm. This makes the wheel bearing unit suitable for commercial vehicles, particularly trucks. Preferably, the inner ring has an outer diameter of 80 mm to 120 mm, and the retaining ring has an outer diameter of 88 mm to 140 mm.

[0018] According to a preferred embodiment, each web segment tapers at least partially in the axial direction. For example, each web segment tapers in the circumferential direction, such that its width decreases with increasing distance from the retaining ring. Alternatively, each web segment tapers in the radial direction, such that its height decreases with increasing distance from the retaining ring. For example, each web segment tapers at an angle of at most 45°, preferably at an angle of at most 25°. Thus, the angle between two converging edges is at most 45°, preferably at most 25°. Preferably, all web segments are identical.

[0019] Further measures improving the invention are described in more detail below, together with a description of preferred embodiments of the invention, with reference to the figures. Here, [the following is shown] Figure 1 is a schematic sectional view of a wheel bearing unit according to the invention with a sealing device according to a first embodiment, Figure 2 is an enlarged schematic sectional view of the sealing device according to the first embodiment, Figure 3 is an enlarged schematic sectional view of a sealing device according to the invention according to a second embodiment, and Figure 4 is a schematic perspective sectional view of the sealing device according to the first embodiment.

[0020] Figure 1Figure 1 shows a longitudinal section through a wheel bearing unit 1 according to the invention. The wheel bearing unit 1 is designed as a double-row tapered roller bearing and comprises two outer rings 2.1, 2.2 and two inner rings 3.1, 3.2, between which rolling elements 4.1, 4.2 are arranged in a respective cage 5.1, 5.2. The rolling elements 4.1, 4.2 are designed as tapered rollers and roll on respective raceways formed on the respective outer ring 2.1, 2.2 and on the respective inner ring 3.1, 3.2. The two inner rings 3.1, 3.2 each abut one another with one of their two end faces, thus forming an interface 7. A sealing device 6 is provided for sealing this interface 7. The sealing device 6 consists of a retaining ring 8 with a sealing element 9. The retaining ring 8 has several axially extending web segments 10, each of which has a radially extending projection 11. One of the two inner rings 3.The wheel bearing unit 1 has a recess 12 in its outer circumferential surface, with the projection 11 on the respective web segment 10 being received in the recess 12 on the inner ring 3.1 when the wheel bearing unit 1 is assembled. This positions and axially holds the sealing element 9 at the interface 7 to prevent the ingress of foreign matter and the leakage of lubricant through the interface 7. The wheel bearing unit 1 is intended for a truck, wherein the respective inner rings 3.1, 3.2 can have an outer diameter of 59 mm to 140 mm, and the retaining ring 8 can have an outer diameter of 65 mm to 160 mm.

[0021] In Figure 2 An enlarged section of the wheel bearing unit 1 according to the invention is shown, with the sealing device 6 in focus. As can be seen from Figure 2As can be seen, the two inner rings 3.1, 3.2 form an annular groove, which is created by a corresponding recess in the area of ​​the outer circumferential surface of the two inner rings 3.1, 3.2 adjacent to the end face. The recess on inner ring 3.1 facilitates the assembly of the retaining ring 8. The sealing element 9 is made of a rubber-elastic material and has two contact points that contact the retaining ring 8 and one contact point each for an inner ring 3.1, 3.2. This design presses the sealing element 9 radially against the inner rings 3.1, 3.2 in the assembled state and thus clamps it radially. This has the advantage that even if the inner rings 3 are axially displaced, the radial seal and the radial clamping of the sealing element 9 remain unaffected. The web segments 10 are formed integrally with the retaining ring 8.Each web segment 10 is formed from a central section 13 with a projection 11 and a centering section 14. The projection 11 is formed integrally with the central section 13 of the respective web segment 10, while the centering section 14 is formed integrally with the central section 13 and extends axially away from the retaining ring 8. Thus, the retaining ring 8 is monolithic and is preferably made of a plastic by injection molding. The centering section 14 abuts the projection 11 axially. The central section 13 can be 3.5 mm to 9.5 mm long. The centering section 14 can be 0.1 mm to 5 mm long. Therefore, each web segment 10 can have an axial length of 3.5 mm to 14.5 mm without axial overlap with the retaining ring 8. Each web segment 10 has a first axial stop for the sealing element 9.The retaining ring 8 has several stop elements 15, which serve as secondary axial stops for the sealing element 9. A transition area 16 with a rounded contour is formed between the retaining ring 8 and the respective web segment 10. The transition area 16 can have a length of 18% to 40% of the central section 13 of the respective web segment 10. The radius of the transition area 16 can be from 0.5 mm to 3 mm. These dimensions determine, in particular, the stiffness of the web segments 10. The recess 12 is formed as a circumferential groove in the outer circumferential surface of the inner ring 3.1 and almost completely accommodates the projection 11. In this case, the projection 11 has a rounded contour, which is essentially cylindrical with a semicircular cross-section. The axial dimension of the projection 11 can be from 12% to 45% of the length of the central section 13 of the respective web segment 10.The respective bridge segment 10 tapers in the axial direction such that the height decreases with increasing distance from the retaining ring 8.

[0022] Matching the geometries and dimensions of the retaining ring 8 is advantageous for the assembly process, making it more efficient. During the assembly of the sealing device 6, the retaining ring 8 with sealing element 9 is first pressed onto the inner ring 3.1. Once the retaining ring 8 reaches its final position, the web segments 10 with their respective projections 11 snap into the groove-shaped recess 12 of the inner ring 3.1, thus axially fixing the retaining ring 8 with the sealing element 9. The inner ring 3.2 is then inserted axially beneath the sealing element 9. The axial force exerted by the inner ring 3.2 on the sealing element 9 through overlap is less than the axial force required to radially push the projections 11 out of the recess 12 in the inner ring 3.1.

[0023] In particular, the radial force of the web segments 10, which is essentially adjusted via the respective transition area 16, is selected to be large enough to prevent the projections 11 from disengaging from the recess 12 of the inner ring 3.1. Furthermore, the geometric design of the projections 11 and recess 12, as well as the geometry and dimensions of the web segments 10, also ensures that the projections 11 are as difficult as possible to disengage from the recess 12 under operating loads, and that the sealing element 9 remains axially positioned.

[0024] Figure 3 Figure 1 shows a second embodiment of the sealing device 6. The sealing device 6 according to the second embodiment differs from the sealing device 6 according to the first embodiment by a different geometry of the projection 11. The projection 11 according to Figure 3It also has a rounded contour; however, the rounded contour does not have a semicircular cross-section, but rather a rectangular cross-section with rounded corners. Other rounded contours for the projection 11, for example a hemisphere, are also advantageous. Otherwise, the sealing device 6 according to the second embodiment corresponds to the sealing device 6 according to the first embodiment, to which reference is made here.

[0025] In Figure 4 The first embodiment of the sealing device 6 is shown in perspective and in section. Figure 4It is evident that the web segments 10 are arranged uniformly around the circumference of the retaining ring 8. Furthermore, the stop elements 15 are also arranged uniformly around the retaining ring 8, with the sealing element 9, designed as a sealing ring, being arranged axially between the web segments 10 and the stop elements 15. In particular, the rounded contour of the transition area 16 between the retaining ring 8 and the respective web segment 10, as well as the circumferentially cylindrical or at least partially ring-shaped projection 11 on the respective web segment 10, are also visible. Furthermore, the respective web segment 10 tapers not only in the axial direction but also in the circumferential direction, such that the width of the respective web segment 10 decreases with increasing distance from the retaining ring 8. Reference symbol list

[0026] 1 Wheel bearing unit 2.1 Outer ring 2.2 Outer ring 3.1 Inner ring 3.2 Inner ring 4.1 Rolling element 4.2 Rolling element 5.1 Cage 5.2 Cage 6 Sealing device 7 Interface 8 Retaining ring 9 Sealing element 10 Web segment 11 Raised section 12 Recess 13 Center section 14 Centering section 15 Stop elements 16 Transition area

Claims

1. A wheel bearing unit (1) for a vehicle having at least one outer ring (2.1, 2.2) and at least two inner rings (3.1, 3.2), between which rolling elements (4.1, 4.2) guided in a respective cage (5.1, 5.2) are arranged, wherein two adjacent inner rings (3.1, 3.2) come into contact with each other with their mutually facing axial end faces at an interface (7), wherein a sealing device (6) is provided for sealing the interface (7) of the two inner rings (3.1, 3.2), wherein the sealing device (6) is formed by a retaining ring (8) having at least one sealing element (9), wherein the retaining ring (8) comprises a plurality of axially formed web segments (10), each of which has a radially formed projection (11), wherein at least one of the two adjacent inner rings (3.1, 3.2) has a recess (12) in an outer circumferential surface for at least partially receiving the projection (11) on the respective web segment (10), characterised in that the respective projection (11) is formed in one piece on a central section (13) of the respective web segment (10), wherein a centering section (14) is formed in one piece on the central section (13) and extends in the axial direction away from the retaining ring (8).

2. The wheel bearing unit (1) according to claim 1, characterised in that the recess (12) is formed as a circumferential groove in the outer circumferential surface of one of the two adjacent inner rings (3.1, 3.2).

3. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the web segments (10) are formed in one piece on the retaining ring (8) and are arranged evenly distributed in the circumferential direction on the retaining ring (8).

4. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that a respective transition area (16) between the retaining ring (8) and the respective web segment (10) has a rounded contour and has at least 18% to at most 40% of the length of the central section (13) of the respective web segment (10).

5. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the projection (11) has a rounded contour.

6. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the respective web segment (10) forms a first axial stop for the at least one sealing element (9), wherein the retaining ring (8) has a plurality of stop elements (15) as second axial stops for the at least one sealing element (9).

7. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the recess has a depth of at least 0.5% to at most 10% of the outer diameter of the respective inner ring (3.1, 3.2).

8. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the respective inner ring (3.1, 3.2) has an outer diameter of 59 mm to 140 mm, wherein the retaining ring (8) has an outer diameter of 65 mm to 160 mm.

9. The wheel bearing unit (1) according to any one of the preceding claims, characterised in that the respective web segment (10) tapers at least partially in the axial direction.