Wheel hub with centering device

Abstract

Wheel hub (1) with a radially extending wheel flange (17) having mounting holes (3), with a cylindrical extension extending axially towards the vehicle side from the wheel flange (17) for at least partially receiving a rolling bearing, and with a centering device arranged axially on the wheel side, concentric to the axis of rotation (R) of the wheel hub (1), which is provided for receiving a wheel rim or brake disc, wherein the centering device is formed from webs (7) separated from each other in the circumferential direction by recesses (8), characterized in that a first web (7) and a second web (7) are arranged in a first radial direction (A) of a first mounting bore (3) of the wheel flange (17), and wherein the first and second webs (7) cover a second opening angle (β) in the plane of the axial contact surface (15) of the wheel flange (17) or a plane parallel thereto.which is defined by the width of a bore recess (6) in the circumferential direction.

Description

[0001] The invention relates to a wheel hub with a radially extending wheel flange having mounting holes, a cylindrical extension extending axially from the wheel flange towards the vehicle side for at least partially receiving a rolling bearing, and a centering device arranged axially on the wheel side, concentric to the axis of rotation of the wheel hub, which is provided for receiving a wheel rim and / or a brake disc. The invention further relates to a wheel bearing unit with a wheel hub of this type.

[0002] This type of wheel hub or wheel bearing unit is used in the automotive sector, particularly in passenger cars. The wheel flange with centering device typically forms the interface for the rim or brake disc and allows the rim of a wheel to be centered on the wheel hub as easily as possible and then fastened.

[0003] A centering device on a wheel hub is typically implemented as a hollow cylindrical body that is axially mounted on the wheel flange and is designed to move the rim / brake disc axially along its axis of rotation. Once the wheel rim is placed on the centering device, no further movement occurs in the radial direction. This allows the wheel rim to be rotated around the centering device into the correct mounting position until the mounting holes of the rim align with the mounting holes of the wheel flange. Typically, the mounting holes of the wheel flange have an internal thread, allowing a force-fit and / or form-fit connection between the rim and the wheel flange to be established using screws. These screws are inserted through the mounting hole in the rim into the corresponding mounting hole in the wheel flange and tightened.

[0004] Such centering devices are already known in the prior art; for example, patent application DE 10 2005 061 389 A1 is cited, in which just such a cylindrical extension is used as a centering device on a wheel hub. Patent application EP 1 500 524 A2 also discloses a wheel hub with a centering device, wherein this centering device is formed by webs separated by recesses.

[0005] On the one hand, there is an effort to ensure the simplest possible wheel assembly by using the aforementioned centering device; however, an equally important goal is a wheel hub that is very lightweight yet still provides the necessary strength. Weight reduction is also a central theme in the aforementioned patent application, where the wheel flange itself is provided with corresponding recesses that do not affect, or only minimally affect, the stiffness while simultaneously reducing weight. Summary of the invention

[0006] The invention is based on the objective of providing a wheel hub with a simple mounting option for brake discs and / or rims, wherein the wheel hub should be easy to manufacture and also have sufficient strength at a low weight.

[0007] This problem is solved in a wheel hub of the type mentioned above by forming the centering device from webs separated from each other by recesses in the circumferential direction. The reduced material results in the weight saving.

[0008] The invention is based on the understanding that the centering device need not be a cylindrical centering device that is continuous in the circumferential direction, but should merely be designed to accommodate the hollow cylindrical fit of the rim / brake disc. Thus, the centering device, insofar as the receiving function is not affected, can be used to achieve an optimal compromise between the weight, strength, and stiffness of the wheel hub.

[0009] The wheel hub according to the invention has a radially extending wheel flange with mounting holes and is designed for attaching the wheel rim. Furthermore, the wheel hub has a cylindrical extension extending axially from the wheel flange on the vehicle side for at least partially accommodating a rolling bearing. It is possible that the extension itself forms a rolling element raceway or is designed to accommodate at least one bearing ring or several bearing rings that form a rolling element raceway.

[0010] The centering device is arranged axially on the wheel side, concentrically to the axis of rotation of the wheel hub. It is designed to accommodate the wheel rim insofar as it can be used as an axial guide and radial centering device for the rim during assembly. The wheel flange has an axial contact surface in the plane of the openings of the mounting holes, with this plane serving as an axial stop surface for the rim. In the following, the terms mounting holes and mounting holes are used synonymously, since mounting holes are usually created by drilling.

[0011] According to the invention, the centering device is formed from webs separated from each other circumferentially by recesses. The webs have a radially outer segment of a cylindrical surface, the curvature of which is defined by the outer radius of the centering device. This radius extends from the axis of rotation of the wheel hub to the outer surface of a web. The number of webs and their circumferential length can vary. If the stiffness of the wheel hub is not critically important, it is quite possible that only three webs are sufficient to ensure a centering function. For wheel hubs of passenger cars, five webs and five mounting holes are generally most suitable. Ideally, the number of webs corresponds to the number of mounting holes. The recesses between the webs can be chosen to be sufficiently large so that the overall weight is not excessive.

[0012] In this configuration, a first web is arranged in a first radial direction of a first mounting hole of the wheel flange, and a second web is arranged in a second radial direction. This is advantageous when stiffness is also a factor in addition to weight reduction.

[0013] Advantageously, the circumferential lengths of the webs correspond to a defined radian measure of the rotation angle. For example, a web could correspond to π / 3 or 60 degrees if the centering device is formed by three webs separated by three recesses, and both the webs and the recesses have the same circumferential length. If, for instance, a wheel flange has five mounting holes, the centering device can consist of five webs and five recesses, all having, for example, the same radian measure of π / 5 or 36 degrees. Alternatively, the recesses can be chosen to be larger or smaller, with an angle δ of 32 degrees for the recesses and an angle γ of 40 degrees for the webs proving effective. This results in a strength-optimized centering device whose recesses have a shorter circumferential length than the webs.Strength can be further optimized by arranging the web associated with the mounting hole radially closer to the mounting hole than to the axis of rotation of the wheel hub.

[0014] Since the wheel flange extends radially furthest of all the wheel hub components, leverage forces arise during operation that must be absorbed by the wheel hub. These leverage forces are transferred from the rim to the wheel flange via the bolts and mounting holes.

[0015] A radial direction is defined as a direction in a plane of rotation that points radially outward from the axis of rotation. Therefore, a radial direction is always perpendicular to the axis of rotation. Stiffness can be increased by aligning a web with a mounting hole of the wheel flange in the same radial direction. In most cases, the web will be axially offset from the mounting hole, but radially, it lies between the axis of rotation and the corresponding mounting hole. In other words, the axial offset is disregarded. During force transmission, the leverage force acts primarily radially toward the axis of rotation, allowing the web to exert a stiffness-enhancing effect from the outside precisely where the force is applied within the wheel flange.

[0016] Furthermore, the first and second webs cover a second opening angle, defined by the circumferential width of a bore receptacle. The bore receptacle serves to prevent the fastening hole from tearing out by dissipating the forces radially inwards into the wheel flange. Therefore, the bore receptacle, as a force transmission element, must also be considered in the design of the webs, depending on the application. The bore receptacle is defined by the material of the fastening hole, which is essential for the required force transmission. Radially, the bore receptacle is defined on the outer side by one or more outer radii that form a material-reinforced circumferential area around the fastening screw. Radially on the inner side, the bore receptacle transitions continuously into the wheel flange body.

[0017] Advantageously, the first and second webs, lying in the plane of the axial contact surface of the wheel flange or a parallel plane, cover a first opening angle. This first opening angle is defined by the diameter of the mounting hole. In other words, the first opening angle is partially formed by a first leg that lies in the plane of rotation and originates on the axis of rotation. Furthermore, the first leg is tangent to the cylindrical shape of the mounting hole on one side. The second leg of the first opening angle also lies in the plane of rotation, originates on the axis of rotation, and is tangent to the cylindrical shape of the mounting hole on the other side. Together with the diameter of the mounting hole, the two legs form an equilateral triangle.

[0018] In an advantageous embodiment, adjacent bores of the wheel flange clamp at the same angle in a plane of rotation, in particular an angle of 90 degrees or 72 degrees. Since the plane of the axial contact surface of the wheel flange is generally arranged perpendicular to the axis of rotation, it may form one of the aforementioned planes of rotation. The angles mentioned represent optimal solutions when using four or five bolts, which must be equipped with the corresponding webs.

[0019] Advantageously, the number of webs equals the number of mounting holes in the wheel flange, although an integer multiple, possibly with differently sized recesses between the webs, is also conceivable. This usually has a positive effect on the manufacturing of the wheel hub and also leads to advantages elsewhere, such as in the packaging. However, the main advantage in terms of stiffness is that in every radial direction to which a mounting hole can be assigned, there is also a web that serves to absorb the radial forces.

[0020] According to a further aspect of the invention, the wheel bearing unit comprises a wheel hub with a radially extending wheel flange having mounting holes, with a cylindrical extension extending axially towards the vehicle side from the wheel flange for at least partially receiving a rolling bearing, and with a centering device arranged axially on the wheel side concentric to the axis of rotation of the wheel hub, which is provided for receiving a wheel rim or brake disc, wherein the centering device is formed from webs separated from one another in the circumferential direction by recesses, and the centering device is formed from five webs and five recesses, wherein the number of webs is equal to the number of mounting holes.

[0021] Advantageously, with a large number of mounting holes, each mounting hole of the wheel flange can be assigned a rib that is arranged in the same radial direction as the associated mounting hole. The number of ribs can be greater than the number of mounting holes.

[0022] Furthermore, the design of the recesses between the webs can also contribute to a compromise between lightness and stiffness. For example, the recesses, or even just selected recesses, between the adjacent webs can form a rounded section. This rounded section transfers forces much more efficiently from one web to the next, especially if the rounded section forms a groove on each web, which may then be combined into a single rounded section. The rounded section, or a portion thereof, can then form the bottom of the recess, which, together with the two adjacent webs, creates a circular hole open in the axial direction.

[0023] Another advantageous embodiment involves arranging the base of the recess in the plane of the axial contact surface of the wheel flange or parallel to this plane. This also takes into account stresses radiating from the wheel flange into the webs, allowing them to be optimally absorbed. If necessary, only a portion of the base lies in the plane of the axial contact surface. This results in a manufacturing advantage. Alternatively, stiffness can be increased by positioning the bases of the recesses not in the axial contact surface, but axially offset from it. This means that the webs initially have a cylindrical shape at their transition from the wheel flange, which is continuous in the circumferential direction. However, the aforementioned centering device, formed by the webs and also featuring recesses, adjoins this cylindrical shape axially.

[0024] The wheel hub according to the invention can advantageously be used in wheel bearing units which have a rolling bearing mounted on the cylindrical extension extending axially from the wheel flange on the vehicle side, wherein the rolling bearing is in particular a double-row or multi-row angular contact ball bearing. Bearing rings, or at least one bearing ring, can be held or preloaded by a cold-formed rolling rivet collar.

[0025] Further advantageous embodiments and preferred further development of the inventions can be found in the description of the figures and / or the dependent claims.

[0026] The invention will now be described and explained in more detail with reference to the exemplary embodiments shown in the figures. Brief description of the characters

[0027] They show: Fig. 1 a wheel bearing unit with a wheel hub having five mounting holes and the associated ribs of the centering device, Fig. 2 the wheel hub from Fig. 1, Fig. 3 the wheel hub Fig. 1 in a cutaway view, Fig. 4 the wheel bearing unit Fig. 1 in cutaway view, and Fig. 5 the wheel bearing unit from Fig. 1 with opening angles of the webs and recesses on the centering device. Character description

[0028] Fig. Figure 1 shows a wheel bearing unit 2 with a star-shaped wheel hub, a centering device with 5 ribs 7 and the recesses 8 between them, and a rolling bearing mounted on the wheel hub.

[0029] The wheel bearing unit 2 can be screwed onto a wheel carrier using the mounting bore 14 on the outer ring 13 of the wheel bearing unit 2. The position of the wheel flange 17 is hardly relevant because the circumferential gaps between the mounting bores 3 of the wheel flange 17 are designed with so little material that a screw can be screwed into a mounting bore 14 almost independently of the position of the wheel flange 17.

[0030] The webs 7 are each located between a mounting hole 3 of the wheel flange 17 and the axis of rotation R. The webs 7 rise axially above the axial contact surface 15 of the wheel flange 17, but lie radially in the same direction as the corresponding mounting holes 3. This is shown by way of example with the radial directions A, which are in the Fig. 1 is schematically indicated by an arrow. The webs 7 are arranged radially essentially centrally between the axis of rotation R and the respective mounting hole 3.

[0031] The webs form a cylindrical centering device, separated from each other circumferentially by radially oriented round holes that are open axially. In this embodiment, the round holes form the exceptions 8.

[0032] The exceptions 8 can also take other forms. For example, the base of the exceptions 8 could lie in the area of ​​the axial contact surface 15, and the circumferentially oriented flanks of the webs could be parallel to each other, thus creating a rectangular recess 8 which, although easy to manufacture, has less stiffness than the solution shown in the figures. Alternatively, the recesses can also have a V-shape, in which the flanks together form an angle that opens in the axial direction. The latter embodiment is particularly easy to manufacture.

[0033] The axial length of the webs 7 is not significant, with an equal height for all webs 7 being the easiest to manage.

[0034] The wheel flange 17 is defined in its radial outer area by various radii. These radii can be equal in magnitude, but are taken into account such that sections 18 are oriented radially outwards both convexly and concavely. The sections 18 are separated from each other by dividing lines 19, making the design of the star-shaped wheel flange 17 particularly simple.

[0035] The bore receptacles 6 encompass the mounting bores 3 radially and are formed by two successive convex sections 18. In the remaining outer area of ​​the wheel flange 17, convex and concave sections 18 alternate. In this way, an intermediate elevation 5 is formed between each pair of adjacent mounting holes 3, which contributes to the overall stiffness of the wheel bearing flange 17.

[0036] In one of the intermediate elevations 5 a bore 4 is provided, which is intended for the attachment of a brake disc.

[0037] Fig. Figure 2 shows the wheel hub 1 of the wheel bearing unit 2. Fig. 1. In a particular embodiment, the web 7 can cover the first opening angle α, which is defined by the two legs originating on the axis of rotation R and tangent to the mounting bore 3 of the wheel flange 17 in a plane of rotation. The web 7 shown significantly exceeds this first opening angle, so that although the wheel hub 1 is heavier, it exhibits improved stiffness. The webs 7 even cover the second opening angle β, which is defined by the radian dimension of the bore receptacle 6. For lighter wheel hubs, the webs 7 can be reduced so that their radian dimension corresponds to either the first or second opening angle α,β, or lies between the two.

[0038] Fig. Figure 3 shows wheel hub 1. Fig. 2 in a cutaway view, showing the rolling rivet collar 9, which secures the inner ring 11 (see Fig. 4) can absorb and preload the rolling bearing.

[0039] The wheel hub 1 also forms a rolling element raceway 10 on the cylindrical extension extending axially from the wheel flange on the vehicle side, which forms part of the rolling bearing.

[0040] In Fig. Figure 3 clearly shows, based on the section through the mounting hole 3, that the web 7, just like the cut mounting hole 3, is arranged in the radial direction A in relation to the axis of rotation R.

[0041] Fig. Figure 4 shows a cutaway view of the wheel bearing unit 2, which is designed as an angular contact ball bearing unit and has two rows of rolling elements 12, which are preloaded via the inner ring 11 and the outer ring 13 relative to the wheel hub 1 in such a way that they can be screwed onto a wheel carrier (not shown) by means of the mounting holes 14 without preloading or preload correction of the rolling bearing.

[0042] Fig. Figure 5 highlights a specific combination of opening angles for ribs and recesses. The wheel hub has a centering device with a height h of 10 millimeters, formed by five ribs and five recesses, where the opening angle γ associated with the ribs 7 is 40 degrees and the opening angle δ associated with the recesses is 32 degrees. This embodiment has proven to be a practical solution.

[0043] In the illustrated embodiments, the number of recesses 8 in the rim seat area of ​​the wheel hub 1 corresponds to the number of mounting holes 3 on the wheel flange 17. However, this is not mandatory; several intermediate webs can also be provided that cannot be assigned to any mounting hole. This also allows for increased component strength of the wheel hub.

[0044] In summary, the invention relates to a wheel hub with a radially extending wheel flange having mounting holes, a cylindrical extension extending axially from the wheel flange towards the vehicle side for at least partially accommodating a rolling bearing, and a centering device mounted axially towards the wheel. The stated objective of the invention is to achieve high stiffness of the wheel hub or the wheel bearing unit with minimal material usage. One possibility arises from recognizing the centering device of a wheel hub as the subject of a compromise between stiffness and possible material recesses. For this purpose, a special arrangement of the webs forming the centering device is proposed, which leads to a particularly advantageous solution, namely, that the webs are oriented in the same radial direction as the mounting holes of the wheel flange. Reference symbol list A first radial direction of a mounting hole of the wheel flange B second radial direction of another mounting hole of the wheel flange D Diameter of the mounting hole h axial height of the centering device R axis of rotation α first opening angle β second opening angle δ Opening angle of the recesses γ Opening angle of the bridges 1 wheel hub 2 Wheel bearing unit 3 mounting holes 4 brake disc mounting holes 5 Interim Survey 6 bore mounts 7 Bridge 8 Exclusion 9 Roll rivet head 10. Raceway of the rolling elements 11 Inner ring 12 rolling elements 13 Outer ring 14 Mounting hole of the mounting flange 15 axial contact surfaces 16 cylindrical extensions 17 Wheel flange 18 rounded section 19 dividing line

Claims

[1] Wheel hub (1) with a radially extending wheel flange (17) having mounting holes (3), with a cylindrical extension extending axially towards the vehicle side from the wheel flange (17) for at least partially receiving a rolling bearing and with a centering device arranged axially towards the wheel side, concentric to the axis of rotation (R) of the wheel hub (1), which is provided for receiving a wheel rim or brake disc, wherein the centering device is formed from webs (7) separated from each other in the circumferential direction by recesses (8), characterized by, that in a first radial direction (A) of a first mounting bore (3) of the wheel flange (17) a first web (7) and in a second radial direction (B) a second web (7) are arranged and wherein the first and second web (7) cover a second opening angle (β) in the plane of the axial contact surface (15) of the wheel flange (17) or a plane parallel thereto, which is defined by the width of a bore receptacle (6) in the circumferential direction. [2] Wheel hub according to claim 1, wherein the first and second web (7) cover a first opening angle (α) in the plane of the axial contact surface (15) of the wheel flange (17) or a plane parallel thereto, which is defined by the diameter of the fastening bore (3) belonging to the respective web (7). [3] Wheel hub according to one of the preceding claims, wherein the webs (7) are radially associated with the mounting holes (3) of the wheel flange (7) with respect to the axis of rotation (R). [4] Wheel hub according to one of the preceding claims, wherein adjacent bore receptacles (6) of the wheel flange (17) span the same angle, in particular an angle of 72 degrees or 90 degrees, in the plane of the axial contact surface (15). [5] Wheel hub according to one of the preceding claims, wherein the number of webs (7) is equal to the number of mounting holes (3) of the wheel flange (17) or is an integer multiple and several webs (7) can be assigned to one mounting hole. [6] Wheel hub according to claim 5, wherein in a plurality of fastening bores (3) of the wheel flange (17) a web (7) can be assigned to each fastening bore which is arranged in the same radial direction (a) as the assigned fastening bore (3). [7] Wheel hub according to one of the preceding claims, wherein at least one recess (8) forms a rounding between two adjacent webs (7) or a bottom of the recess is arranged in the plane of the axial contact surface (15) of the wheel flange (17) or parallel to this plane. [8] Wheel bearing unit comprising a wheel hub (1) according to any of the preceding claims. [9] Wheel bearing unit comprising a wheel hub (1) with a radially extending wheel flange (17) having mounting holes (3), with a cylindrical extension extending axially towards the vehicle side from the wheel flange (17) for at least partially receiving a rolling bearing and with a centering device arranged axially towards the wheel side, concentric to the axis of rotation (R) of the wheel hub (1), which is provided for receiving a wheel rim or brake disc, wherein the centering device is formed from webs (7) separated from each other in the circumferential direction by recesses (8), characterized by, that the centering device is formed from five ribs (7) and five recesses (8), wherein the number of ribs (7) is equal to the number of mounting holes (3). [10] Wheel bearing unit according to claim 9, wherein each mounting bore (3) of the wheel flange (17) can be assigned a web (7) which is arranged in the same radial direction as the assigned mounting bore (3).

Images