Wheel hub assembly for a motor vehicle

Abstract

A wheel hub assembly (1) for a motor vehicle, comprising a wheel hub (2) rotatably mounted by means of a wheel bearing (8) for fastening a wheel (4), wherein a shaft (12) formed separately from the wheel hub (2) is coupled to the wheel hub (2) in a rotationally fixed manner, wherein a first receiving portion (19) of a seal receptacle (20) is formed in the wheel hub (2), in which a sealing device (21) is arranged, which engages in a second receiving portion (22) of the seal receptacle (20), formed in the shaft (12) and adjoining the first receiving portion (19) in the axial direction with respect to a rotational axis (14) of the wheel hub (2), wherein the sealing device (21) bears sealingly against an inner circumferential surface (25) of the wheel hub (2) and against an inner circumferential surface (27) of the shaft (12), characterized in thatthat the sealing device (21) projects beyond the wheel hub (2) on its side facing away from the shaft (12) and has a radial projection (28) there to form a rim cover (29), which projects beyond the first receiving section (19) in the radial direction.

Description

[0001] The invention relates to a wheel hub arrangement for a motor vehicle, with a wheel hub rotatably mounted by means of a wheel bearing for fastening a wheel, wherein a shaft formed separately from the wheel hub is coupled to the wheel hub in a rotationally fixed manner, wherein a first receiving section of a seal receptacle is formed in the wheel hub, in which a sealing device is arranged which engages in a second receiving section of the seal receptacle formed in the shaft and adjoining the first receiving section in the axial direction with respect to an axis of rotation of the wheel hub, wherein the sealing device bears sealingly against an inner circumferential surface of the wheel hub and against an inner circumferential surface of the shaft.

[0002] The wheel hub assembly serves to support the wheel, in particular to rotatably support the wheel, relative to a body of the motor vehicle. The wheel hub assembly has the wheel hub, to which the wheel or a rim of the wheel can be fastened. The wheel hub is in turn rotatably mounted by means of a wheel bearing, in particular on a wheel carrier, so that the wheel as a whole is rotatably mounted. The wheel is connected to the wheel carrier via the wheel hub and the wheel bearing or is mounted on the wheel carrier. The wheel carrier, in turn, is articulated to the body, for example by means of at least one vehicle link. The vehicle link can be designed as a wishbone or a longitudinal link.

[0003] In addition to the wheel hub, the wheel hub assembly also includes a shaft. This shaft is coupled to the wheel hub in a rotationally fixed manner. The shaft is formed separately from the wheel hub and subsequently connected to it during assembly of the wheel hub assembly. For example, the wheel hub and thus the wheel of the motor vehicle can be driven via the shaft. The wheel is thus present as a drivable wheel of the motor vehicle, or a wheel axle to which the wheel is assigned is present as a drivable wheel axle.

[0004] For example, the prior art document DE 10 2014 210 732 A1 is known. This document describes a bearing arrangement for a wheel hub of a motor vehicle that is driven via a rotary joint. The wheel hub, connected to a wheel flange, and the rotary joint, connected to a drive shaft, are connected to one another in a rotationally fixed manner. The bearing arrangement comprises a double-row rolling bearing mounted on the wheel hub with at least one separate inner bearing ring arranged axially on the outside and directed toward the rotary joint, which is axially preloaded by a collar of the wheel hub acting on an end face of the inner bearing ring.

[0005] A sheet metal sealing ring rests against the bearing inner ring. The sealing ring comprises a sealing element that forms a sealing contact with the swivel joint to protect the area between the bearing inner ring, the collar, and the swivel joint, particularly from moisture and dirt. The sealing element has a sealing lip provided with a plurality of recesses. The recesses are evenly distributed circumferentially along the sealing lip and separated from one another by webs to reduce friction between the sealing lip and the swivel joint when the sealing ring is pushed onto the swivel joint.

[0006] Furthermore, the publication DE 31 40 373 A1 describes a wheel bearing unit for driven wheels of motor vehicles. It consists of an inner ring with an axially through bore, an outer ring attached to the chassis, and rolling elements rotating between them. The inner ring has a directly adjacent, radially outwardly extending mounting flange on its output side. On the outer side surface of the mounting flange, there are means for centering these parts that engage in the bore of a wheel rim or brake disc.

[0007] In order to enable a robust and precisely centric fastening of the wheel rim and / or brake disc to the inner ring with economical production of the inner ring and at the same time to ensure a shock-resistant seal of the driving pivot joint in the bore of the inner ring towards the output side, the means for centering the wheel rim or brake disc are formed by a centering ring which has a fastening section with its outer surface tightly set in the bore of the inner ring and a wall section which completely closes its bore.

[0008] The publication DE 10 2005 054 284 A1 discloses a constant velocity joint-wheel hub assembly, wherein the wheel hub comprises a sleeve portion for receiving a wheel bearing and a flange for bolting a wheel, and wherein the constant velocity joint comprises an annular outer joint part with openings at both ends, wherein axial clamping means penetrate the sleeve portion and engage through an opening in the outer joint part, and wherein the sleeve portion and outer joint part are in axially mutually supporting contact. The axial clamping means comprise a hollow body that is supported on the wheel hub and the outer joint part. Form-engagement means for transmitting torque between the wheel hub and the constant velocity joint are formed between the sleeve portion and the outer joint part.

[0009] Furthermore, the prior art documents FR 3 019 092 B1, US 6 524 012 B1 and DE 10 2007 018 803 A1 are known.

[0010] It is an object of the invention to propose a wheel hub assembly for a motor vehicle which has advantages over known wheel hub assemblies, in particular has a lower weight and / or is easier to assemble.

[0011] This is achieved according to the invention with a wheel hub assembly having the features of claim 1. It is provided that the sealing device projects beyond the wheel hub on its side facing away from the shaft and has a radial projection there to form a rim cover, which projects beyond the first receiving portion in the radial direction.

[0012] Basically, it is provided that a first receiving section of a seal receptacle is formed in the wheel hub, in which a sealing device is arranged which engages in a second receiving section of the seal receptacle formed in the shaft and adjoining the first receiving section in the axial direction with respect to an axis of rotation of the wheel hub.

[0013] The wheel hub assembly thus has the seal receptacle, which has its first receptacle section in the wheel hub and its second receptacle section in the shaft. The two receptacle sections of the seal receptacle, i.e. the first receptacle section and the second receptacle section, adjoin one another in the axial direction with respect to the axis of rotation of the wheel hub. In particular, the first receptacle section merges directly into the second receptacle section. The second receptacle section is preferably located in a shaft journal that engages the wheel hub. To form the second receptacle section, the shaft journal is hollow at least in some regions, in particular continuously in the axial direction.

[0014] In other words, the first receiving portion of the seal receptacle is circumferentially bounded by an inner circumferential surface of the wheel hub, and the second receiving portion is bounded by an inner circumferential surface of the shaft, in particular an inner circumferential surface of the shaft journal. Both the wheel hub and the shaft each have a recess, which forms the first receiving portion and the second receiving portion of the seal receptacle, respectively.

[0015] The seal receptacle is preferably arranged centrally with respect to the rotational axis, so that the rotational axis coincides with a longitudinal center axis of the seal receptacle. Preferably, a longitudinal center axis of the first receptacle section and a longitudinal center axis of the second receptacle section are also congruent. Both receptacle sections are thus centered with respect to the rotational axis.

[0016] The sealing device serves to seal the first receiving section and / or the second receiving section from the external environment of the wheel hub assembly. For this purpose, the sealing device bears at least partially against an inner circumferential surface of the seal receptacle, in particular continuously in the circumferential direction with respect to the axis of rotation. The sealing device preferably consists of a sealing material, for example of an elastic material, for example of plastic, in particular of an elastomer. Of course, however, the sealing device can also be made of metal or at least comprise metal. For example, it can be provided that the sealing device has a stiffening core made of a stiffer material, which is enclosed by a sealing sleeve made of a softer material.

[0017] Preferably, the sealing device is held in the seal receptacle in a force-fitting manner. To this extent, it is inserted or pressed into the seal receptacle. Although the sealing device bears against the wheel hub and / or the shaft, it preferably does not exert any holding effect between them. The sealing device is therefore not intended to fix the shaft axially relative to the wheel hub. If the sealing device bears against both the wheel hub and the shaft, at most a slight holding effect can occur due to the force-fitting fastening of the sealing device in the seal receptacle.

[0018] For example, the sealing device consists of a central body from which at least one sealing projection extends radially outwards. For example, this sealing projection bears against the wheel hub or the shaft. The central body itself has dimensions in the radial direction that are smaller than the dimensions of the first receiving section and / or the second receiving section of the seal receptacle. Preferably, the dimensions of the central body in the radial direction, based on the dimensions of the smallest of the receiving sections in the radial direction, are at most 0.75, at most 0.5, or at most 0.25. Such a configuration significantly reduces the amount of material required for the sealing device, so that overall, regardless of the material of the sealing device, a drastic reduction in the weight of the wheel hub assembly is achieved.

[0019] A further embodiment of the invention provides that the shaft has, on its side facing the wheel hub, a drive shaft journal engaging in the wheel hub, in particular a drive shaft journal connected to a joint hub of a constant velocity joint or cardan joint. The shaft is coupled to another shaft via the joint hub, wherein the another shaft can have an axis of rotation that is different from the axis of rotation of the shaft, in particular is angled with respect to it. The shaft thus forms a component of a drive shaft, for example a constant velocity shaft or a cardan shaft. Accordingly, the joint hub is a component of the constant velocity joint or the cardan joint. The joint hub is connected to the shaft journal mentioned above, which in this respect can also be referred to as a drive shaft journal. The connection between the joint hub and the shaft journal is preferably rigid.In particular, the joint hub and shaft journal are designed as one piece and / or made of the same material.

[0020] A preferred embodiment of the invention provides that the shaft, in particular the shaft journal, has a toothing for rotationally fixed coupling with the wheel hub, which toothing meshes with a mating toothing of the wheel hub. In this case, it can be provided that the shaft or the shaft journal engages with the wheel hub. In this case, the toothing of the shaft is designed as external toothing present on the shaft journal, which meshes with the mating toothing of the wheel hub, which is designed as internal toothing. Alternatively, it is possible for the shaft to engage around the wheel hub. In this case, the toothing of the shaft is designed as internal toothing, which meshes with the mating toothing, which is then present as external toothing.It is of course also possible for the shaft and the wheel hub to each have an external toothing running in the circumferential direction or a frontal toothing, whereby the external toothings interact to ensure a rotationally fixed coupling between the shaft and the wheel hub.

[0021] A further development of the invention provides that the first receiving section extends completely through the wheel hub in the axial direction. The first receiving section is thus open on both sides of the wheel hub in the axial direction or, as viewed in longitudinal section, in the wheel hub. It has a mouth opening facing away from the shaft and a mouth opening facing the shaft, with the shaft engaging the wheel hub through the mouth opening, for example. The complete penetration of the wheel hub by the first receiving section allows a significant reduction in the weight of the wheel hub.

[0022] Within the scope of a preferred embodiment of the invention, it is provided that the sealing device bears sealingly against the inner circumferential surface of the wheel hub with a first sealing projection. The inner circumferential surface of the wheel hub delimits the first receiving section of the seal receptacle in the radial direction. To seal the seal receptacle, the sealing device now bears against the inner circumferential surface, in particular continuously in the circumferential direction. For this purpose, the sealing device has the first sealing projection, which can be in the form of a radial sealing lip. The first sealing projection preferably extends from the base body of the sealing device already described above. The outer dimensions of the first sealing projection in the radial direction are, for example, at least 1.5, at least 2.0, at least 2.5, at least 2.75 or at least 3.0, based on the dimensions of the base body in the same direction.

[0023] A further preferred embodiment of the invention provides that the sealing device bears sealingly against the inner circumferential surface of the shaft with a second sealing projection. The bearing against the inner circumferential surface of the shaft can be provided in addition to or alternatively to the bearing against the inner circumferential surface of the wheel hub. For this purpose, the sealing device has the second sealing projection, which can basically be designed analogously to the first sealing projection. Reference is therefore made to the corresponding embodiments. However, the outer dimensions of the second sealing projection in the radial direction are preferably smaller than the outer dimensions of the first sealing projection. Relative to the outer dimensions of the second sealing projection in the radial direction, the outer dimensions of the first sealing projection in the same direction are, for example, at least 1.25, at least 1.5, at least 1.75 or at least 2.0.

[0024] Within the scope of a further embodiment of the invention, it can be provided that the drive shaft journal is designed as a hollow journal and the inner circumferential surface is present in the drive shaft journal. The use of the hollow journal can further reduce the weight of the wheel hub assembly. However, because a grease chamber of the constant velocity joint or universal joint is delimited in the direction of the wheel hub by the solid drive shaft journal in other designs of the wheel hub assembly, it is now necessary to create a seal that delimits the grease chamber. This seal is represented by the sealing device, which for this purpose rests against the inner circumferential surface. For this purpose, the inner circumferential surface is assigned to the drive shaft journal and is therefore located in it.

[0025] The invention provides that the sealing device projects beyond the wheel hub on its side facing away from the shaft and has a radial projection there to form a rim cover, which projects radially beyond the first receiving section. The sealing device thus penetrates the seal receptacle, starting from the shaft or the second receiving section, to its side facing away from the shaft. There, it projects beyond the wheel hub. At its end facing away from the shaft, the sealing device has the radial projection which forms the rim cover. The rim cover thus forms an integral part of the sealing device and is therefore not a component to be mounted separately.

[0026] The rim cover is, for example, adapted in terms of shape and / or dimensions to a wheel hub receptacle of the wheel rim. This means that the rim cover, for example, completely engages over the wheel hub receptacle or, alternatively, rests against its inner circumferential surface, in particular continuously in the circumferential direction. In the latter case, the rim cover has dimensions, for example in the radial direction, that correspond to the dimensions of a wheel rim seat of the wheel hub. The wheel rim seat of the wheel hub serves to arrange the wheel rim on the wheel hub. For example, the wheel hub engages with its wheel hub seat in the wheel hub receptacle of the wheel rim, namely in such a way that an outer circumference of the wheel rim seat of the wheel hub rests continuously in the circumferential direction against an inner circumferential surface of the wheel hub receptacle of the wheel rim. Accordingly, the rim cover projects beyond the first receiving section in the radial direction, i.e., has larger dimensions.

[0027] A preferred development of the invention provides that the shaft is fixed in the axial direction relative to the wheel hub by means of a fixing means that is different from the sealing device. It has already been pointed out above that the sealing device does not exert a holding effect on the wheel hub relative to the shaft, or vice versa. Accordingly, for axially fixing the shaft relative to the wheel hub in the axial direction, the fixing means that is different from the sealing device must be provided.

[0028] The fixing means is, for example, in the form of a snap ring, which engages, on the one hand, in a recess extending through the outer circumferential surface of the shaft and, on the other hand, in a recess formed in the inner circumferential surface of the wheel hub or the receiving section. In this respect, the fixing means replaces, for example, an otherwise provided central screw by means of which the wheel hub and the shaft are fastened to one another.

[0029] Finally, within the scope of a further preferred embodiment of the invention, it can be provided that the second receiving section completely penetrates the shaft in the axial direction. The second receiving section therefore adjoins the first receiving section on the one hand, or opens into it, as seen in the axial direction or in longitudinal section. On the other hand, it penetrates the shaft in the direction away from the wheel hub. For example, it opens into the shaft journal or passes through it. The second receiving section can therefore serve at least partially to hold a lubricant for the joint. In particular, a grease chamber of the joint, namely the constant velocity joint or cardan joint, is present in the second receiving section. The grease chamber is preferably formed at least partially in the shaft journal.

[0030] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawing, without limiting the invention. The only Figure is a schematic longitudinal sectional view of a wheel hub arrangement for a motor vehicle.

[0031] The figure shows a schematic longitudinal section of a wheel hub assembly 1 for a motor vehicle. The wheel hub assembly 1 has a wheel hub 2, to which a wheel rim 3 of a wheel 4 of the motor vehicle can be fastened. For example, the wheel rim 3 has a wheel hub receptacle 5, while the wheel hub 2 has a wheel rim seat 6. After the wheel 4 has been mounted on the wheel hub 2, the wheel hub 2 engages with its wheel rim seat 6 in the wheel hub receptacle 5 of the wheel rim 3. In addition, a brake disc 7 can be arranged on the wheel hub 2, by means of which the wheel 4 can be braked. The wheel hub 2 is rotatably mounted by means of a wheel bearing 8, namely with respect to a wheel carrier (not shown in detail). In the exemplary embodiment shown here, the wheel bearing 8 is designed as a multi-row, in particular a double-row, rolling bearing. Accordingly, it has rolling elements 11 arranged between an inner ring 9 and an outer ring 10.

[0032] Also part of the wheel hub assembly 1 is a shaft 12, which is present, for example, as part of a propeller shaft. Accordingly, the shaft 12 has a joint hub 13, which is located in particular on the side of the shaft 12 facing away from the wheel hub 2. The joint hub 13 is, for example, part of a constant velocity joint or cardan joint. The shaft 12 is formed separately from the wheel hub 2 and is coupled to it in a rotationally fixed manner. In the exemplary embodiment shown here, the shaft 12 engages the wheel hub 2, namely with a shaft journal or propeller shaft journal.

[0033] For the rotationally fixed coupling of the shaft 12 with respect to the wheel hub 2, an external toothing of the shaft 12 (not shown here) meshes with an internal toothing of the wheel hub 2 (also not shown). The external toothing is preferably located on the shaft journal. To additionally fix the shaft 12 in the axial direction with respect to a rotational axis 14 of the wheel hub 2, a fixing means 15 is provided. This is in the form of a snap ring 16, which engages on the one hand in a receptacle 17 of the shaft 12 and on the other hand in a receptacle 18 of the wheel hub 2. The receptacle 17 engages through an outer circumferential surface of the shaft 12, and the receptacle 18 engages through an inner circumferential surface of the wheel hub 2.

[0034] A first receiving section 19 of a seal receptacle 20 is formed in the wheel hub 2. A sealing device 21 is arranged in this receiving section 19 and extends into a second receiving section 22 of the seal receptacle 20, which adjoins the first receiving section 19. The second receiving section 22 of the seal receptacle 20 is formed in the shaft 12, more precisely, at least partially in the shaft journal. Preferably, the first receiving section 19 extends completely through the wheel hub 2 and / or the second receiving section 22 extends completely through the shaft 12 or the shaft journal in the axial direction.

[0035] The sealing device 21 has a base body 23, which, viewed in cross-section relative to the rotational axis 14, is, for example, round. A first sealing projection 24, which is, for example, in the form of a sealing lip, extends from the base body 23. The first sealing projection 24 bears against an inner circumferential surface 25 of the wheel hub 2, which radially delimits the first receiving portion 19 of the seal receptacle 20. For example, the sealing projection 24 is angled relative to the rotational axis 14, viewed in longitudinal section, in particular such that it is inclined radially outward in the direction facing away from the shaft 12.

[0036] Additionally or alternatively, a second sealing projection 26 is provided, which also extends radially outwards from the base body 23. The second sealing projection 26 bears against an inner circumferential surface 27 of the shaft 12, wherein the inner circumferential surface 27 is preferably present in the shaft journal. Analogous to the first sealing projection 24, the second sealing projection 26 can be inclined with respect to the axis of rotation 14, in particular in the direction facing away from the shaft 12 or in the direction facing the wheel rim 3. Both the first sealing projection 24 and the second sealing projection 26 bear sealingly against the respective inner circumferential surface 25 or 27, in particular continuously in the circumferential direction. The first sealing projection 24 is also arranged at a distance from the shaft 12 in the axial direction or, viewed in the axial direction, bears against the inner circumferential surface 25 of the wheel hub 2 at a distance from the shaft 12.

[0037] On its side facing away from the shaft 12, the sealing device 21 has a radial projection 28 that forms a rim cover 29. The radial projection 28 is preferably round in cross-section. It can be designed such that it bears against an inner circumferential surface 30 of the wheel hub receptacle 5 of the wheel rim 3, in particular continuously in the circumferential direction. However, it can also protrude beyond the wheel rim 3 in the direction facing away from the shaft 12 and bear sealingly against an end face 31 of the wheel rim 3. In any case, however, the rim cover 29 closes the wheel hub receptacle 5 in the direction facing away from the wheel hub 2. Accordingly, it has larger dimensions in the radial direction than the first receiving section 19 of the sealing receptacle 20 or is at least the same size.

[0038] The wheel hub assembly 1 described here has the advantage of being extremely lightweight and also easy to assemble. Because the shaft 12 is fixed axially relative to the wheel hub 2 by means of the fixing means 15, the sealing device 21 can be arranged in the seal receptacle 20. The sealing device 21 preferably consists of a sealing material, but at least of a material that has a lower seal than the material of the wheel hub 2 and / or the material of the shaft 12. This and the small dimensions of the sealing device 21 in the radial direction, in particular of the base body 23, result in a very low weight. In addition, the shaft journal of the shaft 12 is hollow at least in some areas, preferably continuously, and is therefore designed as a hollow journal.

Claims

[1] Wheel hub assembly (1) for a motor vehicle, comprising a wheel hub (2) rotatably mounted by means of a wheel bearing (8) for fastening a wheel (4), wherein a shaft (12) formed separately from the wheel hub (2) is coupled to the wheel hub (2) in a rotationally fixed manner, wherein a first receiving portion (19) of a seal receptacle (20) is formed in the wheel hub (2), in which a sealing device (21) is arranged, which engages in a second receiving portion (22) of the seal receptacle (20) formed in the shaft (12) and adjoining the first receiving portion (19) in the axial direction with respect to a rotational axis (14) of the wheel hub (2), wherein the sealing device (21) bears sealingly against an inner circumferential surface (25) of the wheel hub (2) and against an inner circumferential surface (27) of the shaft (12), characterized bythat the sealing device (21) projects beyond the wheel hub (2) on its side facing away from the shaft (12) and has a radial projection (28) there to form a rim cover (29), which projects beyond the first receiving section (19) in the radial direction. [2] Wheel hub assembly according to claim 1, characterized by that the shaft (12) has, on its side facing the wheel hub (2), a shaft journal engaging in the wheel hub (2). [3] Wheel hub arrangement according to one of the preceding claims, characterized by that the shaft (12) has a toothing for the rotationally fixed coupling with the wheel hub (2) which meshes with a counter toothing of the wheel hub (2). [4] Wheel hub arrangement according to one of the preceding claims, characterized by that the first receiving section (19) completely penetrates the wheel hub (2) in the axial direction. [5] Wheel hub arrangement according to one of the preceding claims, characterized bythat the sealing device (21) with a first sealing projection (24) bears sealingly against the inner circumferential surface (25) of the wheel hub (2). [6] Wheel hub arrangement according to one of the preceding claims, characterized by that the sealing device (21) with a second sealing projection (26) bears sealingly against the inner circumferential surface (27) of the shaft (12). [7] Wheel hub arrangement according to claim 2, characterized by that the shaft journal is designed as a hollow journal and the inner peripheral surface (27) is present in the shaft journal. [8] Wheel hub arrangement according to one of the preceding claims, characterized by that the shaft (12) is fixed in the axial direction with respect to the wheel hub (2) by means of a fixing means (15) different from the sealing device (21). [9] Wheel hub arrangement according to one of the preceding claims, characterized by that the second receiving section (22) completely penetrates the shaft (12) in the axial direction.

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