Wheel bearing unit for vehicle

Abstract

The invention relates to a wheel bearing unit (1) for a drive train of a vehicle, in particular a motor vehicle, comprising: a wheel bearing hub (5) having a first spur gear (6); a joint cover (3) for driving the joint, the joint cover having a second spur device (7); a radially prestressing element (10), which is accommodated in the recess (9) such that, in an elastically unstressed state, the radially prestressing element protrudes at least partially from the recess (9) in the radial direction (R); and an at least partially conical peripheral surface (15) which, in the at least partially assembled state of the wheel bearing unit (1), is arranged opposite the radially prestressing element (10) in the radial direction (R), the radially prestressing element (10) and the at least partially conical peripheral surface (15) interacting during the assembly of the wheel bearing unit (1), the radially prestressing element (10) is arranged in the wheel bearing hub (5) such that an axial force (17) is generated which supports the wheel bearing hub (5) and the joint cover (3) against each other, the radially prestressing element (10) being non-circular.

Description

Technical Field

[0001] The invention relates to a wheel bearing unit for a drive train of a vehicle, in particular a motor vehicle. Background Art

[0002] In various embodiments, wheel bearing units for motor vehicles are known from the prior art. In this respect, it is known to provide power transmission between a drive shaft and a wheel bearing hub via radial toothing or spur toothing. For example, a spur toothing can be provided on a joint cover or a cardan shaft that engages with a drive shaft of the motor vehicle. The spur toothing of the joint cover can in turn engage with a correspondingly designed spur toothing of the wheel bearing hub, so that a corresponding torque of the drive shaft can be transmitted to the wheel bearing hub.

[0003] The assembly of the wheel bearing unit is relatively complicated here, because the wheel bearing hub is usually first attached to the wheel carrier and then the joint cover is inserted into the wheel carrier, wherein the connection between the wheel bearing hub and the joint cover via the spur gearing is established in a blind assembly manner. As a result, during the assembly of the joint cover and the wheel bearing hub, it may happen that the teeth of the spur gearing of the joint cover and the teeth of the spur gearing of the wheel bearing hub meet instead of meshing with each other. This means that the teeth of the spur gearing of the joint cover do not engage in the tooth gaps of the spur gearing of the wheel bearing hub. When the joint cover and the wheel bearing hub are supported in this so-called tooth-to-tooth position of the two spur gearings, the tooth heads of the two spur gearings are pressed onto each other and can only enter the so-called tooth-to-tooth position in which the two spur gearings mesh at a later point in time and with a relatively large amount of force. This can lead to a loss of preload in the joint cover / wheel bearing hub connection and / or damage to the spur gearing. In particular, various solutions are known in the prior art to prevent a reduction in the preload.

[0004] For example, DE 10 2007 057 047 A1 discloses a method for assembling a hub component having a shaft coupling part connected thereto in a rotationally fixed manner and a corresponding connection device. In the prior art, snap rings are used to connect the coupling cover and the hub and to avoid a tooth-to-tooth position in a spur gear arrangement, in which the two components are pulled together. These snap rings are usually circular.

[0005] It has now become apparent that there is a need to improve the known wheel bearing units for vehicles, in particular to provide a spur gear bearing unit which is not only easier to assemble but also ensures a secure connection between the spherical joint and the wheel hub, which is also cost effective. A tooth-to-tooth position of a spur gear arrangement should also be avoided.

[0006] Against this background, it is an object of the present invention to provide an improved wheel bearing unit for a vehicle, which wheel bearing unit can be assembled more easily, which wheel bearing unit ensures a secure connection between the joint cover and the wheel hub and which wheel bearing unit is cost-effective. Summary of the invention

[0007] This and other objects which a person skilled in the art may mention or recognize upon reading the following description are achieved by the subject matter of the independent claims. Advantageous embodiments and other improvements can be found in the dependent claims and the following description.

[0008] The wheel bearing unit for a drive train of a vehicle, in particular a motor vehicle, according to the invention comprises: a wheel bearing hub having a first spur gearing; a coupling cover of a drive coupling having a second spur gearing; a circumferentially and radially preloadable element; and a peripheral surface formed at least partially conically. The radially preloadable element is accommodated in a circumferential recess in such a way that in the elastically stress-free state, the radially preloadable element protrudes at least partially from the recess in the radial direction and also at least partially into the recess. In the at least partially assembled state of the wheel bearing unit, the conical peripheral surface is arranged opposite the radially preloadable element in the radial direction. Here, the radially preloadable element and the conical peripheral surface interact during the assembly of the wheel bearing unit so that an axial force is generated, which supports or preloads the wheel bearing hub and the coupling cover against each other. The radially preloadable element is non-circular.

[0009] A non-circular shape of the radially preloadable element is understood to mean a shape that deviates from a circle.Due to the non-circular shape of the radially preloadable element, the element does not lie on the circumferential surface over its entire outer surface, but only at certain contact points.

[0010] The radially preloaded circumferential element can be designed as annular, star-shaped or slotted when closed, i.e., as annular or star-shaped when opened. In addition, the radially preloaded circumferential element can also be designed as an ellipse, a teardrop shape, etc., wherein the radially preloaded element can also be designed to be closed or slotted, i.e., open in these shapes. In particular, the star-shaped and / or open radially preloaded circumferential element can achieve improved guidance in the recess and / or can achieve greater radial expansion. For example, the radially preloaded element can be designed as a rubber ring, such as an O-ring. In addition, the radially preloaded circumferential element can be designed, for example, as a spring retaining ring, which can be made of plastic or a plastic mixture or a metal or a metal alloy. The axial force can also be referred to as the axial preload force.

[0011] The advantage of the solution according to the invention lies in particular in the fact that the contact of the radially preloadable element with the conical peripheral surface generates a radial force due to the elastic stress state of the radially preloadable element, which in combination with the conical peripheral surface generates an axial force in the assembly direction, whereby the wheel bearing hub and the joint cover are supported against each other. This means that during assembly of the wheel bearing unit, the wheel bearing hub and the joint cover cannot be easily separated even if the first spur gearing and the second spur gearing are in a tooth-on-tooth position. In this state, the tooth-on-tooth position of the first spur gearing and the second spur gearing is achieved by a small rotational relative movement between the wheel bearing hub and the joint cover. Due to the axial force, the wheel bearing hub and the joint cover are then held in the tooth-on-tooth position, in which they can then be firmly supported together by means of a supporting element, for example a clamping screw.

[0012] Snapping the resiliently preloadable element into the tapered peripheral surface also makes the connection less likely to become detached, since the resiliently preloadable element has to deform elastically against radial forces in a direction opposite to the assembly direction, which can only be achieved by applying an external force.

[0013] In other words, a wheel bearing unit is proposed with a preloaded snap-in device in order to produce a tooth-to-tooth assembly between a first spur gearing of the wheel bearing hub and a second spur gearing of the joint cover. Furthermore, such a snap-in device hardly requires any additional installation space, which is why the installation space requirement of the wheel bearing unit remains essentially unchanged.

[0014] According to one embodiment of the wheel bearing unit, the radially preloadable element has a plurality of contact points resting on the circumferential surface. The outer surface of the preloadable element between these contact points does not rest on the circumferential surface. This generates an additional spring force between the contact points, which causes the total spring force of the preloadable element to increase in the radial direction. This effect can even reduce the cross-section of the preloadable element without sacrificing the radial spring force. This has the advantages of cost savings and size reduction. Due to the increased radial spring force of the radially preloadable element according to the invention, a more secure connection between the joint cover and the wheel hub can be achieved without increasing costs.

[0015] According to another embodiment of the wheel bearing unit, the radially preloadable element has three contact points resting on the circumferential surface. The three contact points are preferably arranged at an angle of approximately 120° relative to one another, so that the three contact points are evenly distributed over the circumference of the preloadable element. This arrangement results in an optimal spring surface between the contact points, so that the radial spring force is optimally increased.

[0016] However, it is also conceivable that a different arrangement of contact points distributed over the circumference may be provided. For example, it is also conceivable to provide only two contact points, for example arranged opposite each other. However, it is also conceivable to provide four or more contact points, symmetrically or asymmetrically arranged over the circumference of the preloadable element.

[0017] According to another preferred embodiment of the wheel bearing unit, the radially preloadable element has an opening which extends in particular over an angle between 10° and 45°. The opening in this region preferably refers to the unassembled or unpreloaded state of the element. The opening allows the preloadable element to spring open and snap into the recess without reducing the radially acting spring force.

[0018] Preferably, the radially preloadable element of the wheel bearing unit has at least two, in particular three, windings. The preloadable element is wound several times like a spring. By means of the at least two windings, the radial spring force can be further increased. This design allows the cross section of the preloadable element to be reduced without reducing the radially acting spring force.

[0019] According to a further preferred embodiment of the wheel bearing unit, the radially preloadable element has an outer diameter which is greater than the sum of the inner diameter of the radially preloadable element and three times the cross section of the radially preloadable element.

[0020] Preferably, the radially preloadable element is made of spring steel or plastic. These materials have optimal spring properties so that good radial spring forces can be generated.

[0021] According to another embodiment of the wheel bearing unit, the radially preloadable element has a substantially circular cross section. This design allows the preloadable element to snap into a correspondingly designed recess.

[0022] The radially preloadable element is preferably mounted without play in the recess.The radially preloadable element preferably centers the joint cover and the hub relative to each other.

[0023] Advantageously, the recess is arranged on the outer diameter of the joint cover and the tapered peripheral surface is arranged on the inner diameter of the wheel bearing hub, wherein the inner diameter of the wheel bearing hub is larger than the outer diameter of the joint cover. Due to the recess on the outer diameter of the joint cover, the radially preloadable element is easy to assemble and can be designed in particular as a circlip. Alternatively, according to another embodiment, the recess is arranged on the inner diameter of the wheel bearing hub and the tapered peripheral surface is arranged on the outer diameter of the joint cover, wherein the inner diameter of the wheel bearing hub is larger than the outer diameter of the joint cover. The recess on the inner diameter of the wheel bearing hub also allows the use of inexpensive O-rings as radially preloadable elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following uses the drawings in conjunction with the description of the preferred exemplary embodiments of the present invention to illustrate further measures for improving the present invention. In the drawings:

[0025] Figure 1A shows a schematic partial representation of a wheel bearing arrangement according to one embodiment of the invention;

[0026] Figure 1B shows a perspective view of a radially preloadable element according to the prior art;

[0027] Figure 2 A radially preloadable element according to one embodiment of the invention is shown.

[0028] The drawings are merely schematic in nature and are only useful for understanding the invention. Identical elements are provided with the same reference numerals. DETAILED DESCRIPTION

[0029] Figure 1A An exemplary schematic partial representation of a wheel bearing unit 1 for a vehicle according to the invention is shown in longitudinal section, the wheel bearing unit having a wheel bearing 2 and a joint cover 3. The wheel bearing 2 has a rolling bearing 4 and a wheel bearing hub 5, on which the rolling bearing 4 is arranged in an axially fixed manner. The wheel bearing hub 5 also has a first spur gearing 6, which engages in a torque-transmitting manner with a second spur gearing 7 on the joint cover 3 in the assembled state of the wheel bearing unit 1.

[0030] exist Figure 1A In the embodiment, the joint cover 3 also has a recess 9 on the outer diameter 8, in which a radially preloadable element 10 is arranged so that in the elastically unstressed state, the radially preloadable element at least partially protrudes outwardly from the recess 9 in the radial direction R. In this respect, the recess 9 is designed so that it can substantially completely accommodate the volume of the radially preloadable element 10 in the elastically stressed state.

[0031] The radially preloadable element 10 is made in particular of plastic, a plastic mixture, metal or a metal alloy and is advantageously designed as a snap ring 11. The wheel bearing hub 5 has on the inner side 12 a guide surface 13, a tapered diameter 14 and a conical peripheral surface 15, wherein the tapered diameter 14 is smaller than the guide surface 13 of the wheel bearing hub 5 but larger than the outer diameter 8 of the joint cover 3.

[0032] The guide surface 13 is formed in an inclined, in particular conical manner so that the radially preloadable element slides along the guide surface 13 when the joint cover 3 is inserted into the wheel bearing hub 5 and is thus gradually elastically compressed. The gradual elastic compression of the radially preloadable element 10 makes it easier to guide it through the contraction diameter 14. After passing the contraction diameter 14, the radially preloadable element 10 expands outwards again in the radial direction until it comes into contact with the conical peripheral surface 15. Here, the conical peripheral surface 15 is designed so that the cone tapers in the axial direction A towards the contraction diameter 14. This means that the radially preloadable element 10 cannot transition to an elastically stress-free state after passing the contraction diameter 14, so that a radial force 17 acting on the conical peripheral surface 15 is generated in the contact area 16 between the radially preloadable element 10 and the conical peripheral surface 15. Due to the tapered, i.e. inclined, course of the tapered peripheral surface 15 in longitudinal section, a radial force 17 acting perpendicularly on the tapered peripheral surface 15 generates an axial force 18 acting in the axial direction A which supports the wheel bearing hub 5 and the joint cover 3 minimally or lightly against each other in the assembly direction M. The axial force 18 may also be referred to as an axial preload force 18 .

[0033] In this respect, the tapered diameter 14 and the tapered peripheral surface 15 are arranged in the axial direction A such that the radially preloadable element 10 has, so to speak, “snapped” behind the tapered diameter 14 when the spur gearing 6, 7 is in the tooth-on-tooth position and has therefore generated an axial force 18. The axial force 18 supports the wheel bearing hub 5 and the joint cover 3 against each other in the tooth-on-tooth position during assembly of the wheel bearing unit 1, so that the joint cover 3 cannot fall out of the wheel bearing hub 5 again. The tooth-on-tooth position, which can also be referred to as the tooth-on-clearance position, can be generated by a rotational relative movement between the wheel bearing hub 5 and the joint cover 3, wherein the axial force 18 is designed to axially preload the wheel bearing hub 5 and the joint cover 3 against each other also in the tooth-on-tooth position, thereby also preventing the joint cover 3 from falling out of the wheel bearing hub 5 in the tooth-on-tooth position.

[0034] Furthermore, the wheel bearing hub 5 has a rear surface 19 which is arranged downstream of the tapered peripheral surface 15 when viewed in the assembly direction M. The rear surface 19 may be formed in an oppositely tapered shape relative to the tapered peripheral surface 15 (see FIG. Figure 1A) or substantially cylindrical. The rear surface 19 serves to accommodate the radially preloadable element 10 after assembly of the wheel bearing unit 1, in particular after the wheel bearing hub 5 and the joint cover 3 have been supported by support elements 20, such as clamping screws, and thus prevent the radially preloadable element 10 from sliding out of the recess 9. In particular, the oppositely conical rear surface 19 can elastically stress or elastically compress the radially preloadable element 10, so that the radially preloadable element 10 is supported in the recess so that it is substantially unable to move in the operating state of the wheel bearing unit 1. The substantially cylindrically designed rear surface 19 prevents the radially preloadable element 10 from sliding out of the recess 9, but the radially preloadable element 10 can move between the cylindrical rear surface 19 and the recess 9 and thus cause a clicking sound in the operating state of the wheel bearing unit 1.

[0035] exist Figure 1A In the embodiment, the recess 9 is formed integrally on the outer diameter 8 of the joint cover 3 in a one-piece manner by way of example, wherein the recess is formed as a groove 21. Alternatively, the recess 19 can also be designed as a groove. Both are easy to manufacture and low in cost.

[0036] Particularly preferably, the circumferential surface 15 can be designed such that the wheel bearing hub 5 and the joint cover 3 are pressed apart in the tooth-to-tooth position. In this way, the installer can recognize that there is an incorrect assembly and can take corrective measures. As a result, the radially preloadable element 10 does not snap onto the constricted diameter 14 in the tooth-to-tooth position. In the tooth-to-tooth position, the radially preloadable element 10 can snap onto the constricted diameter 14 and pull the joint cover 3 and the wheel bearing hub 5 together. This enables a tactile assembly control for the installer.

[0037] Figure 1B A radially preloadable element 10 according to the prior art is shown. The radially preloadable element 10 is in particular circular and open on one side to allow compression into the recess 9. Due to its circular design, the radially preloadable element 10, in particular designed as a snap ring 11, rests on the circumferential surface 15 over its entire outer circumference. Only small radial forces 17 are generated here.

[0038] Figure 2A radially preloadable element 10 according to one embodiment of the invention is shown. The radially preloadable element 10 is preferably designed as a snap ring 11 which is open on one side. The radially preloadable element 10 is non-circular, i.e. has a shape which deviates from a circle. The element 10 preferably has a plurality of contact points 10a which, in the mounted state, are in contact with the peripheral surface 15 in the recess 9. Thus, spring surfaces 10b are formed between the contact points 10a which produce a significant increase in the radial force 17 when the preloadable element 10 is mounted. The change in the shape of the preloadable element 10 enables an increased radial force 17 and thus a significantly safer connection between the wheel bearing hub 5 and the joint cover. The preloadable element 10 is mounted without play and centered in the recess 9. The preloadable element 10 is preferably centered on the inner surface via at least two, preferably four, contact points A, B, C, D. Tilting of the preloadable element 10 is prevented.

[0039] Preferably, the preloadable element 10 has three external contact points 10a and preferably four further internal contacts A, B, C, D. Particularly preferably, the preloadable element 10 has an odd number of contact points 10a, preferably uniformly distributed over the circumference. The preloadable element 10 has an opening 10c, which extends in particular over an angle of 10° to 45°, particularly preferably up to 30°. Furthermore, the outer diameter Da of the radially preloadable element 10 is greater than the sum of the inner diameter Di of the radially preloadable element and three times the cross section (s) (Da>Di+3*s).

[0040] Reference numerals list

[0041] 1 wheel bearing unit

[0042] 2 wheel bearings

[0043] 3 Joint cover

[0044] 4 Rolling bearings

[0045] 5. Wheel bearing hub

[0046] 6. First spur gear unit

[0047] 7 Second spur gear device

[0048] 8 outer diameter

[0049] 9 recess

[0050] 10 Radially preloadable elements

[0051] 10a Contact point

[0052] 10b Spring surface

[0053] 10c Open

[0054] 11 Circlip

[0055] 12 Medial part

[0056] 13 Guide surface

[0057] 14 Contraction diameter

[0058] 15 Conical peripheral surface

[0059] 16 Contact area

[0060] 17 Radial force

[0061] 18 Axial force

[0062] 19 Rear surface

[0063] 20 Support elements

[0064] Da outer diameter

[0065] Di inner diameter

[0066] S cross section

[0067] A, B, C, D contact parts

Claims

1. A wheel bearing unit (1) for a drive train of a vehicle, in particular a motor vehicle, the wheel bearing unit comprising: a wheel bearing hub (5), the wheel bearing hub having a first spur gear arrangement (6); a coupling cover (3) of a drive coupling, the coupling cover having a second spur gear arrangement (7); a radially preloadable element (10), the radially preloadable element being accommodated in a recess (9) such that in an elastically stress-free state the radially preloadable element protrudes at least partially from the recess (9) in a radial direction (R); and an at least partially conical peripheral surface (15), the at least partially conical peripheral surface being arranged opposite the radially preloadable element (10) in the at least partially assembled state of the wheel bearing unit (1) in the radial direction (R), wherein: The radially preloadable element (10) and the at least partially conical peripheral surface (15) interact during assembly of the wheel bearing unit (1) so as to generate an axial force (17) which supports the wheel bearing hub (5) and the joint cover (3) against each other, characterized in that the radially preloadable element (10) is non-circular.

2. The wheel bearing unit (1) according to claim 1, characterized in that The radially preloadable element (10) has a plurality of contact points (10a) resting on the peripheral surface (15).

3. The wheel bearing unit (1) according to claim 1 or 2, characterized in that The radially preloadable element (10) has three contact points (10a) resting on the peripheral surface (15).

4. The wheel bearing unit (1) according to claim 2 or 3, characterized in that The contact points (10a) are evenly distributed over the circumference, so that in particular an angle of 120° is provided between the contact points (10a).

5. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The radially preloadable element (10) has an opening (10c) which extends, in particular, over an angle between 10° and 45°.

6. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The radially preloadable element (10) has at least two, in particular three, windings.

7. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The outer diameter (Da) of the radially preloadable element (10) is greater than the sum of the inner diameter (Di) of the radially preloadable element and three times the cross section (s) of the radially preloadable element (10).

8. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The radially preloadable element (10) is made of spring steel or plastic.

9. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The radially preloadable element (10) has a substantially circular cross section (s).

10. Wheel bearing unit (1) according to any one of the preceding claims, characterized in that The recess (9) is formed in the joint cover (3).

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