Rolling-element bearing unit for wheel bearing assembly

A rolling-element bearing unit for a wheel bearing assembly of a vehicle includes a rolling-element bearing with an outer ring, a an inner ring, a bearing interior between the outer ring and the inner ring and a plurality of rolling elements in the bearing interior. The inner ring has an inner ring surface facing the bearing interior and a first and a second axial end surface. A first seal assembly includes a retainer fixed on the bearing outer ring and a seal element configured to slidingly seal against the bearing inner ring surface or against a slip sleeve carried by the bearing inner ring. The retainer is an angle bracket having an axially extending annular leg and a radially inwardly extending annular flange, and radially inwardly extending flange projects radially inwardly beyond the bearing inner ring surface, for example, over a step in the first axial end surface.

This application claims priority to German patent application no. 10 2016 211 781.5 filed on Jun. 29, 2016, the contents of which are fully incorporated herein by reference.

TECHNOLOGICAL FIELD

The present disclosure relates to a rolling-element bearing unit, in particular for a wheel bearing assembly of a vehicle as well as a wheel bearing assembly including such a rolling-element bearing unit.

BACKGROUND

Wheel bearing assemblies, in particular for commercial vehicles, usually include two axially adjacent rolling-element bearings, each including a bearing outer ring and each including a bearing inner ring, between which rolling elements are disposed. During installation into the wheel bearing the bearing inner rings including the roller set and the bearing outer rings are separately assembled and lubricated. In order to provide a simplified installation with such a wheel bearing assembly it is also known to provide the rolling-element bearings as preassembled bearing units. However, it is problematic here that the bearing rings must be secured during transport in order to prevent the respective bearing ring from sipping out of the rolling-element bearing or generally to prevent the rolling-element bearing from falling apart.

It is known from the prior art, for example, to provide a retaining element that secures the bearing rings of the preassembled bearing unit during transport. However, it is disadvantageous here that prior to the installation of the rolling-element bearing unit into the wheel bearing the retaining element must be removed again, with the result that production times and manufacturing costs increase.

In addition, the retaining element cannot safeguard against a dirt ingress, with the result that dirt can enter into the rolling-element bearing during transport or installation. It is also problematic that even with such preassembled bearings a greasing of the bearing must occur during installation, since although the retaining elements hold the bearing rings in their predetermined positions, they do not ensure that lubricant remains in the bearing. It is thus possible for the bearing to be lubricated with an “incorrect” lubricant during installation, which reduces the service life of the bearing.

SUMMARY

It is therefore an aspect of the present disclosure to provide a rolling-element bearing unit for a wheel bearing wherein the bearing rings are secured during transport, they have a lubricant retaining function, and they can be installed into the wheel bearing quickly and in a simple manner.

In the following a rolling-element bearing unit, in particular for a wheel bearing assembly of a vehicle, is presented including a rolling-element bearing that includes a bearing outer ring and a bearing inner ring that define a bearing interior between them wherein rolling elements are disposed. The bearing inner ring furthermore includes a bearing inner ring surface facing the bearing interior and axially terminating end surfaces. In addition the rolling-element bearing unit comprises a first seal assembly that is fixed on the bearing outer ring via a retaining element and carries a seal element that slips against the bearing inner ring surface or a slip sleeve carried by the inner ring and seals the bearing interior.

In order to secure the rolling-element bearing unit against falling apart without a transport safeguard having to be removed prior to installation, it is proposed to configure the retaining element as an angle plate that includes an axially extending annular leg and a radially inwardly extending annular flange, wherein the radially inwardly extending annular flange extends over the bearing inner ring surface. The radially inwardly extending flange thus supports the bearing outer ring on the bearing inner ring and secures the assembled rolling-element bearing against falling apart. The retaining element simultaneously ensures against a penetrating of coarse dirt into the bearing during transport, installing, and operating.

According to one preferred exemplary embodiment the bearing inner ring further includes a step on the end surface associated with the seal assembly, in which step the radially inwardly extending flange is received. A transport securing that is as axially space-saving as possible can thereby be provided.

Here the step preferably includes a radially extending step surface and an axially extending step surface, wherein the radially inwardly extending flange is disposed spaced from the step surfaces and forms a gap seal. This gap seal ensures a particularly good protection against coarse contamination. A more friction-free operating of the rolling-element bearing can simultaneously thereby be ensured.

Furthermore it is advantageous if the step is formed via a slip sleeve pushed on the bearing inner ring, wherein preferably the axially extending step surface is formed via the bearing inner ring surface and the radially extending step surface by an end surface of the slip sleeve. An additional processing of the bearing inner ring is thereby omitted. In addition, existing rolling-element bearings can also be equipped with the seal assemblies. Slip sleeves have the additional advantage that they have particularly smooth surfaces that make possible a wear-free abutting of seal lips, whereby the service life of the bearing can be increased.

According to a further advantageous exemplary embodiment the end surface of the bearing inner ring and an external surface of the radially inwardly extending flange are disposed flush with respect to each other. An installing of the rolling-element bearing on a stub axle including a stub-axle step is thereby also possible.

A further exemplary embodiment shows a rolling-element bearing unit wherein the bearing outer ring is axially elongated on the side of the first seal assembly such that an end side of the bearing outer ring is formed flush with the end side of the bearing inner ring. A particularly good attachment possibility for the retaining element can thereby be provided.

According to a further advantageous embodiment the first seal assembly includes a carrier element rotatably connected to the retaining element, which carrier element is connected to the seal element in a materially-bonded manner, for example, by vulcanizing, and/or in a friction-fit manner, for example, by clamping. Here the carrier element is preferably disposed axially inside the radially inwardly extending flange of the retaining element. An ingress of dirt or water from the external environment into the bearing interior can thereby still be effectively prevented. Furthermore, the seal element can include at least one seal lip that seals with respect to the bearing inner ring and/or a slip sleeve. Alternatively or additionally the seal element can include a preload element, for example, a spring element, which ensures a particularly good sealing.

According to a further preferred exemplary embodiment the rolling-element bearing unit includes a second seal assembly that is disposed on the axial side of the rolling-element bearing opposite the first seal assembly and seals the bearing interior. A rolling-element bearing unit can thereby be provided that includes a bearing interior sealed from an external environment. Such a rolling-element bearing unit can be provided as a preassembled bearing unit pre-filled with lubricant, which can be simply and quickly installed in a wheel bearing. An incorrect filling with “incorrect” lubricant and/or a contaminating due to an water- and/or dirt-ingress into the bearing interior is also reliably prevented. Wheel bearings can thereby also be equipped with preassembled bearing units that require the separate installation of individual rolling-element bearing units.

Here it is preferred if the second seal assembly is connected to the bearing outer ring such that they rotate together and includes a seal element that slips against the bearing inner ring surface or a slip sleeve carried by the bearing inner ring. For the attachment to the bearing outer ring such that the second seal element rotates together with the bearing outer ring, a groove is particularly preferably provided in the outer ring, in which groove the second seal assembly is received.

A further aspect of the present disclosure relates to a wheel-bearing assembly of a vehicle including a rolling-element bearing unit that can be configured as described above.

Further advantages and advantageous embodiments are defined in the description, the claims, or the drawings. Here in particular the combinations of features specified in the description and in the drawings are purely exemplary, so that the features can also be present individually or combined in other ways.

In the following the disclosure shall be described in more detail with reference to the exemplary embodiments depicted in the drawings. Here the exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the pending claims.

DETAILED DESCRIPTION

In the following identical or functionally identically operating elements are indicated by the same reference numbers.

FIG. 1shows a schematic cross-sectional depiction through a wheel bearing assembly100for a vehicle that is depicted sectionally enlarged inFIGS. 2 and 3. Here the wheel bearing assembly shown inFIG. 1is configured as a double row tapered roller bearing2,4, wherein the two tapered roller bearings are disposed in a back-to-back arrangement in order to make possible a high stiffness with respect to lateral forces.

For the sake of simplicity, in the following the tapered roller bearing4is discussed that carries the inventive elements.

The rolling-element bearing4shown inFIG. 1comprises a bearing outer ring6and a bearing inner ring8rotatable with respect thereto, which between them form a bearing interior space10wherein rolling elements12are disposed. Optionally the rolling elements12can be received in a bearing cage14.FIG. 1furthermore shows that axially adjacent to the rolling elements12between the bearing outer ring6and the bearing inner ring8a first, outer seal assembly16is disposed on the outer side of the wheel bearing and a second, inner seal assembly18on the inner side of the wheel bearing, which seal assemblies16and18seal the rolling-element bearing4against an ingress of dirt or water from an external environment. Together the rolling-element bearing4and the seal assemblies16,18form a rolling-element bearing unit1that can be provided as preassembled and pre-lubricated rolling-element bearing unit1and received by a wheel hub.

However, in order to provide for the rolling-element bearing unit1as a preassembled unit, it must not only have a good sealing against an ingress of dirt or a discharge of lubricant, but also be secured against falling apart. Especially with the tapered roller shape depicted here, without some securing mechanism the rolling-element bearing2;4would easily fall apart toward the wheel bearing interior.

Therefore the first seal assembly16is not configured as in the prior art but rather additionally includes, as can be seen in particular inFIG. 2, a retaining element20that secures the bearing outer ring6against axial slipping. The retaining element20is itself configured as an angled metal-plate element including an axial section22that is attached to the bearing outer ring6such that they rotate together, and a radial flange24that extends toward the bearing inner ring8. Here the radial flange24extends at least partially up to over or past or beyond a bearing inner ring surface26.

In order to make possible a particularly good receiving and supporting of the radial flange24on the bearing inner ring8, a step28is formed on the bearing inner ring that includes a radially extending step surface30and an axially extending step surface32. This step can be formed integrally with the bearing inner ring8, however, it is also possible that the step28is formed via a slip sleeve29(FIG. 4) mounted on the bearing inner ring8. Here the radial flange24is supported on the radial step surface30and serves as installation- and transport-safeguard against a falling apart of the rolling-element bearing4.

Furthermore it can be seen fromFIG. 2that a gap remains between the radial flange24and the radial step surface30, and a gap remains between radial flange24and the axial step surface32. These gaps34,36makes possible friction-free movement of the retaining element20with respect to the bearing inner ring8. Simultaneously a gap seal forms here with the result that additional sealing is provided against to the entry of dirt.

FIG. 2also shows that the bearing outer ring6is axially widened such that an end surface38of the bearing outer ring6is flush with an end surface40of the bearing inner ring8. In addition the step28in the bearing inner ring8allows the radial outer surface42of the retaining element20to be flush with the end surface40of the bearing inner ring8or the end surface38of the bearing outer ring6. The rolling-element bearing4can thereby be received in a problem-free manner even on stub axles including a stub-axle step, without the retaining element20having to be removed for installation or the total axial length of the bearing having to be adjusted.

The retaining element20carries the actual first seal assembly16that comprises a carrier element44including a seal element46attached thereto in a materially bonded manner, for example, by vulcanization, or a friction-fit manner, for example, by clamping. On a side facing the bearing interior10the seal element46extends along the carrier element44radially from the bearing outer ring6up to the bearing inner ring8and includes at least one seal lip50, optionally preloaded by a spring element48, that slips against the bearing inner ring8and seals the bearing interior10. Of course all other seal elements known from the prior art are usable for the seal assembly16.

In order to seal the rolling-element bearing4not only on the wheel bearing outer side but also on the wheel bearing inner side, asFIG. 1shows the second seal assembly18, which is depicted enlarged inFIG. 3, is provided on the wheel bearing inner side. The second seal assembly18is also attached to the bearing outer ring6essentially such that they rotate together and includes a radially extending seal ring disc52that radially inwardly carries a seal lip54that slips against the bearing inner ring8. Radially outwardly the seal ring disc52is received in a groove56provided in the bearing outer ring6. Of course this seal assembly can also be formed by another seal known from the prior art.

The rolling-element bearing interior is advantageously protected by the seal assemblies16;18disposed on both sides of the rolling elements at all times, even during installation and during transport, against the entry of dirt and/or water or a discharge of lubricant. Simultaneously the additional retaining element secure the bearing rings against falling apart or axially separating with respect to each other so that an installation- and transport-securing is provided that can even remain on the bearing in the assembled state.

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