Connection arrangement between a wheel bearing unit of a vehicle and a wheel carrier

Abstract

Connection arrangement between a wheel bearing (2) of a vehicle intended for a vehicle wheel and a wheel carrier (1) of a chassis of the vehicle, wherein the wheel bearing (2) rests with a contact surface (2a) on a counter surface (1a) of the wheel carrier (1) and is clamped against this by means of several detachable fastening elements (5) in the form of screws arranged in a ring around an axis of rotation of the wheel bearing (2), characterized in that hard particles (3) are applied to the contact surface (2a) and / or to the counter surface (1a) before the manufacture of the connection arrangement and thus before the assembly of the wheel bearing (2), which project at least partially into the respective other surface (1a, 2a) due to the clamping assembly.

Description

The invention relates to a connection arrangement between a wheel bearing of a vehicle and a wheel carrier, wherein the wheel bearing rests with a contact surface on a counter surface of the wheel carrier and is clamped against this surface by means of releasable fastening elements. The invention further relates to a method for manufacturing a connection arrangement according to the invention. For the prior art, reference is made, by way of example, to DE 10 2014 000 975 A1 and DE 198 36 678 C1. A friction-enhancing coating is known from DE 10 2011 005 921 A1. DE 10 2008 055 706 A1 discloses a device with at least one shaft. A method for increasing the friction between frictionally connected components is known from DE 10 2008 036 796 A1. Furthermore, DE 10 2008 017 029 A1 discloses a friction-enhancing layer on a component. Additionally, US 2014 / 0334868 A1 discloses a structural overlap joint. It is common practice, at least in passenger cars, to detachably fasten wheel bearings (for the vehicle wheels) to so-called wheel carriers of the chassis (which, at least for the present invention, also include steering knuckles or swivel bearings) by means of several screws arranged in a ring around the axis of rotation of the wheel bearing (e.g., shown in DE 10 2009 038 952 A1). As specified in the preamble of claim 1, corresponding surfaces of the wheel bearing and the wheel carrier are clamped against each other (in the manner of a flange connection). It is also known that, under certain circumstances, this fastening technology can cause cracking noises (disturbing noises) in the aforementioned connection arrangement, resulting from micro-movements or minute (micro-)vibrations between these components due to the forces or moments being transmitted in various directions. To remedy this, the first-mentioned document proposes an interference fit between a wheel bearing ring and the wheel carrier. The second-mentioned document proposes, to prevent such creaking noises at a different location, namely between the wheel bearing and a drive shaft for that wheel, that one of the surfaces supported (or clamped) against each other in the direction of rotation of the wheel bearing, which are referred to there as end faces, be designed to compensate for elastic material deformations occurring due to the axial clamping and thus to even out the surface pressures between the joining partners caused by the axial clamping. The object of the present invention is to demonstrate a further effective measure by which the aforementioned cracking noises (occasionally occurring during the operation of the vehicle) in a connection arrangement according to the preamble of claim 1 can be prevented. The solution to this problem is characterized by the fact that hard particles are applied to the contact surface and / or the mating surface before the connection arrangement is manufactured and thus before the wheel bearing is mounted (on the wheel carrier), which, due to (or as a consequence of) the clamping assembly, project at least partially into the other surface. Advantageous embodiments and further developments are the subject of the dependent claims. In particular, a method for manufacturing a connection arrangement is also claimed, which implements at least one process engineering feature contained in the apparatus claims. According to the invention, the coefficient of friction between the clamped surfaces of the wheel bearing on the one hand and the wheel carrier on the other is increased by applying so-called hard particles to at least one of these surfaces before the assembly of the connection arrangement. These particles then dig into the other (opposite) surface, at least partially, during assembly, i.e., during clamping as part of mounting the wheel bearing to the wheel carrier. To reduce or prevent the aforementioned noises or clicking sounds in the connection area between a wheel carrier and a wheel bearing attached to it, the surface finish of at least one of these components is specifically adapted by applying hard particles to the contact surface, such that the coefficient of friction between the contact surface (of the wheel bearing) and the mating surface of the wheel carrier is increased by means of additional positive locking.Viewed on a micro level, when these components are clamped against each other, the hard particles provided according to the invention indent themselves into the surface structure of the respective other component and create a micro-interlocking effect. Silicon carbide, for example, can be used as the material for the hard particles. Such hard particles (made of any suitable material) can have a size ("diameter") of several micrometers (e.g., 1–70) and are characterized not only by exceptionally high hardness but preferably also by extremely sharp edges, meaning their surface preferably has a multitude of corners and edges. It is known that silicon carbide, for example, can be applied to surfaces with extremely good durability using plasma technology; see the so-called "Plasma-Grip" technology of efc plasma GmbH, Ingolstadt. In this process, these hard particles are held on the plasma-coated surface by means of a nickel adhesion promoter layer.It should be expressly noted that the present invention is by no means limited to such hard particles by the mention of this example; rather, various other materials and methods can be used by means of which sufficiently hard particles, when clamping a surface coated with such particles (e.g., the aforementioned contact surface) of, for example, a wheel bearing assembly, in particular against a wheel carrier made of, for example, a (relatively soft) aluminum alloy, at least partially penetrate its surface (= the aforementioned mating surface). A positive fit is thereby created by pressing the hard particles at least partially into the respective mating surface. Furthermore, these hard particles increase the total surface area over which the two components are in contact with each other, which results in an additional increase in the frictional force acting between these components. A layer of hard particles applied according to the invention is naturally particularly effective when the hard particles are applied to at least one of the aforementioned surfaces with at least near-abrasion resistance. This can be achieved, for example, by applying the hard particles using a blasting process such as pressure blasting, injector blasting, or plasma blasting. This makes it possible to apply the hard particles to, for example, the contact surface of the wheel bearing with such high pressure that they partially penetrate the wheel bearing and simultaneously partially protrude from this contact surface. When the wheel bearing is then mounted on the wheel carrier, the portions of the hard particles protruding from the contact surface of the wheel bearing penetrate into the softer material of the wheel carrier and thus into its mating surface as the wheel bearing is clamped to the wheel carrier.(Although the above describes the process of applying the hard particles to the wheel bearing, with a suitable material combination the other approach is of course also possible, namely that the hard particles are first applied to the opposite surface of the wheel carrier and then penetrate its contact surface during assembly of the wheel bearing). Furthermore, when blasting or applying the hard particles to one of the components, they can be selectively applied or introduced into the respective component (wheel bearing and / or wheel carrier) with such a pulse by suitable control of the beam that these hard particles penetrate the component at least approximately halfway and protrude at least approximately halfway from its surface. Several possible blasting methods have already been mentioned above, by means of which hard particles can be applied to at least one of the aforementioned components (wheel bearing, wheel carrier) according to the invention. Regarding the plasma blasting mentioned, the plasma atmospheric pressure blasting method, the low-pressure plasma blasting method, or the vacuum plasma blasting method can advantageously be used. Further exemplary materials for the hard particles provided according to the invention include NiSiC or a nickel-diamond powder, as well as steel, for example in the form of angular particles made of cast stainless steel (called Cr grit), angular chilled cast iron (with a martensitic microstructure), or corundum particles (made of aluminum oxide with a SiO2 content). In principle, hard particles can therefore be applied to a harder material of one of the two components (e.g., the wheel bearing), which then penetrates a softer material of the other component (e.g., the wheel carrier made of a light metal alloy); however, such a material assignment or combination is by no means mandatory.The hard particles can be applied either completely to at least one of the aforementioned ring-shaped surfaces, namely the contact surface (of the wheel bearing) or the mating surface (of the wheel carrier), or only in the vicinity of the aforementioned screws on at least one of the aforementioned surfaces, namely the contact surface or the mating surface. Preferably—but expressly not obligatorily—the hard particles can be applied to at least one of the aforementioned surfaces with at least near-abrasion resistance, for example, as already mentioned, by means of a blasting process. In principle, however, it is also possible to apply such durable particles with only slight adhesion to at least one of the aforementioned surfaces, so that when the components are clamped against each other, they can simultaneously embed themselves partially into both surfaces.For the sake of completeness, reference is made to the present method claims, whereby, in principle, a method can be claimed instead of a device, by claiming that hard particles are applied instead of the feature that hard particles are applied. The accompanying Fig. 1 shows, in the form of a schematic diagram, a greatly enlarged section of a cross-section in the connection area between a wheel carrier 1 and a wheel bearing 2, also referred to as a wheel bearing unit, with the latter resting with its contact surface 2a on the counter surface 1a of the wheel carrier 1. Not shown in Fig. 1 is a bolted connection (using several bolts as releasable fasteners) by which the wheel bearing 2 is clamped against the wheel carrier 1 and held there, similar to a flange connection. Before the manufacture of this bolted connection and thus before the installation of the wheel bearing 2, hard particles 3 were applied to the contact surface 2a of the wheel bearing 2. Due to the clamping action, these particles protrude at least partially into the counter surface 1a of the wheel carrier 1, as shown in Fig. 1.In this case, the hard particles 3 are also held on the contact surface 2a via a nickel adhesion promoter layer 4 - due to this thin nickel adhesion promoter layer 4, a micro gap is created between the two components 1, 2. Figure 2a shows, as a further embodiment, a section of a cross-section in the connection area between a wheel carrier 1 and a wheel bearing 2, the latter only partially resting on the counter-surface 1a of the wheel carrier with its contact surface 2a. Two screw connections 5 (using screws as releasable fasteners) are shown symbolically, by means of which the wheel bearing 2 is clamped against the wheel carrier 1 and held therein in the manner of a flange connection. In a partial area X of the wheel bearing 2, between two adjacent screw connections 5, the immediate vicinity of which is not part of this partial area X, a small recess of material is provided such that the contact surface 2a in this partial area X is spaced apart from the counter-surface 1a of the wheel carrier 1.This measure alone makes it possible to tighten or clamp the wheel bearing 2 more firmly or strongly against the wheel carrier 1 via the (as usual, several, mostly four) screw connections 5, thereby reducing the aforementioned creaking noises. Additionally, in this embodiment, the hard particles 3 according to the invention are applied to the contact surface 2a only in the vicinity of the screw connections 5, namely where the contact surface 2a actually comes into contact with the counter surface 1a during the assembly of the connection. This is shown enlarged in the detail from Fig. 2a depicted in Fig. 2b.

Claims

Connection arrangement between a wheel bearing (2) of a vehicle intended for a vehicle wheel and a wheel carrier (1) of a chassis of the vehicle, wherein the wheel bearing (2) rests with a contact surface (2a) on a counter surface (1a) of the wheel carrier (1) and is clamped against this by means of several detachable fastening elements (5) in the form of screws arranged in a ring around an axis of rotation of the wheel bearing (2), characterized in that hard particles (3) are applied to the contact surface (2a) and / or to the counter surface (1a) before the connection arrangement is manufactured and thus before the wheel bearing (2) is mounted, which project at least partially into the respective other surface (1a, 2a) due to the clamping assembly. Connection arrangement according to claim 1, wherein the hard particles (3) are fully applied to at least one of the ring-shaped said surfaces, namely contact surface (2a) or counter surface (1a). Connection arrangement according to claim 1, wherein the hard particles (3) are applied only in the vicinity of the screws on at least one of said surfaces, namely contact surface (2a) or counter surface (1a). Connection arrangement according to one of the preceding claims, wherein the hard particles (3) are applied to at least one of said surfaces (2a, 1a) in a manner that is at least approximately abrasion-resistant. Connection arrangement according to one of the preceding claims, wherein the hard particles (3) are particles with a size of 1 - 70 µm whose surface has a plurality of corners and edges. Connection arrangement according to one of the preceding claims, wherein the hard particles (3) consist of a steel material or of corundum or of silicon carbide or Ni-SiC (in the form of a nickel-diamond coating). Method for producing a connection arrangement according to one of the preceding claims by applying at least one process engineering feature contained therein. Method according to claim 7, wherein the hard particles (3) are applied to the contact surface (2a) and / or to the counter surface (1a) by a blasting method such as pressure blasting or injector blasting or plasma blasting in such a way that they penetrate the respective component (2, 1) having this surface to a certain extent and protrude from this surface to a certain extent. Method according to claim 7 or 8, wherein the hard particles (3) are introduced into the respective component (wheel bearing 2 and / or wheel carrier 1) with such an impulse that, in relation to their total dimensions, they penetrate at least approximately half into the component (2, 1) and protrude at least approximately half from its surface (2a, 1a).

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