Technical field of the invention

The invention relates to the field of wheel hubs and, in particular, to a hub comprising a particular brake caliper carrying flange.

Known state of the art

Wheel hubs, see for example figure 1 of the prior art, for twin wheels comprise a generally hollow bridge arm, on which there is fitted, on the outside, a bearing. A ring nut G locks the fixed part of the bearing on the bridge arm against a ring called "abutment ring" AB, which is also fixed, usually by means of welding, on the bridge arm and previously ground with it, so as to offer to the fixed part BF of the bearing an annular surface that is sufficiently plane and perpendicular to the axis of development of the bridge arm.

The wheel disc WD, on which the twin wheels will be fixed, is usually formed by two portions WDl and WD2 with an axial symmetry, which are joined by means of an axial interface. In this way, the movable part of the bearing remains axially and annularly locked between the two portions of the wheel disc WDl and WD2. The brake disc BD is associated with the wheel disc, for example with the inner portion WD2 of the wheel disc, or it can be interposed between the wheel disc and the rims WR1 and WR2 of the twin wheels. This brake disc usually has the shape of a bell, whose opening faces the inner part, i.e. the medial part, of the axle.

The brake caliper carrying flange FP is usually welded in an suitable position on the bridge arm.

This solution is aimed at eliminating one of the twin wheels, though keeping the same layout described above. This means that the brake caliper carrying flange can be moved closer, according to an axial direction, to the wheel bearing: in other words, it can be moved to an outer position relative to the development of the bridge arm.

In order to support the brake caliper, the carrying flange must be shaped like a bell, as well, projecting from the apical fixing point, on the bridge arm, towards the brake disc .

This solution is not deemed to be ideal, especially in terms of weight, torsional stresses ecc.

US2008121070 describes a wheel hub whose features are set forth in the preamble of claim 1.

Summary of the invention

An object of the invention, starting from the idea of eliminating a twin wheel, though keeping the relative hub layout described above, is to find an improving solution for fixing the brake caliper carrying flange.

A further object of the invention is to possibly reduce the components used to manufacture a wheel hub.

The idea on which the invention is based is that of using one single component to make both the abutment ring for the fixed part of the wheel bearing and the brake caliper carrying flange.

To make things easier, in the description below, said single element will be referred to as "brake caliper carrying flange" or simply "flange", but let's not forget that it is manufactured and positioned so as to both support the brake caliper and act as an abutment ring for the wheel bearing.

The flange according to the invention allows manufacturers to turn an existing axle for twin wheels into an axle for single wheels.

A further object of the invention is to provide a method to fix said brake caliper carrying flange to the bridge arm.

According to a preferred embodiment of the invention, said brake caliper carrying flange is fixed to the bridge arm by means of welding with the addition of weld material.

Preferably, in order to have a sturdy fixing, both faces of the brake caliper carrying flange are fixed to the bridge arm.

Furthermore, instead of grinding the weld material added during the welding procedure, in order to offer an optimal abutment surface for the bearing, the annular part fitted on the bridged is subjected to an axial machining, so as to define at least three axial projections, which project towards the wheel bearing, so that the added weld material is arranged in such a way that it is entirely contained within said projections.

A following grinding procedure of the abutment ring built-in in the brake caliper carrying flange exclusively involves said axial projections.

According to the invention, there is provided a brake caliper carrying flange according to claim 1.

According to the invention, there is also provided a wheel hub comprising said brake caliper carrying flange.

Finally, according to the invention, there is provided a terrestrial vehicle comprising the aforesaid wheel hub.

We would like to point out that the assembly of two opposite hubs corresponds to the assembly of a vehicle axle .

The claims describe preferred embodiments of the invention, thus forming an integral part of the description .

Brief description of the figures Further objects and advantages of the invention will be best understood upon perusal of the following detailed description of an embodiment thereof (and of relative variants) with reference to the accompanying drawings merely showing non-limiting examples, wherein:

figure 1 shows an axial section of a wheel hub for twin wheels according to the prior art;

figure 2 shows an axial section of a wheel hub implementing, according to the invention, the brake caliper carrying flange according to the invention,

figure 2a shows an enlargement of a portion of figure 2 to highlight aspects linked to the assembly of the wheel hub according to the invention,

figure 3 shows a perspective view of the brake caliper carrying flange.

In the figures, the same numbers and the same reference letters indicate the same elements or components.

We would like to point out that the components shared by the known solution shown in figure 1 and the solution of the invention are indicated with same numbers and letters, so as to stress the fact that the invention deals with an evolution to single wheels of a twin-wheels bridge arm. For the purposes of the invention, the term "second" component does not imply the presence of a "first" component. As a matter of fact, these terms are only used for greater clarity and should not be interpreted in a limiting manner.

Detailed description of embodiments

Figure 2 shows an axial section of a wheel hub "with twin wheels", in which one single wheel is implemented for each side of the axle.

The bridge arm BA has a tubular, elongated shape, axially symmetrical relative to the axis X.

A bearing B is fitted on the bridge arm, with the relative fixed part BF axially locked between the ring nut G and the abutment ring R.

The movable part BM of the bearing B is axially and annularly locked between the two axial portions WDl and WD2 of the wheel disc WD, as described above. In other words, the wheel disc WD is axially fitted on the outside of the mobile part BM of the bearing B.

The wheel disc WD, on which one single wheel WR2 will be fixed, is formed by two portions with an axial symmetry, which are joined by means of an axial interface AF.

The outer axial face WDF of the wheel disc represents the interface to which the brake disc DB and the wheel WR2 are connected. In particular, between the wheel disc and the wheel rim WR2 the brake disc BD' is interposed.

Unlike the implementation for twin wheels, the brake disc BD is preferably connected to the outer axial portion WD1, which is the closest to the free end of the bridge arm BA. It should be clear that, in order to optimize costs, manufacturers can keep implementing the same brake disc BD shown in figure 1 of the prior art, though this would lead to a flange FPR with the relative radial expansions FLR projecting inwards (and not outwards, as shown in figure 2), namely towards the medial part of the bridge arm.

According to the invention, the abutment ring R is made as one single piece together with the brake caliper carrying flange FP, which defines, as the same time, an abutment ring and a brake caliper carrying flange. For this reason it is indicated with FPR (FP+R) .

Said flange FL, obtained in one single piece by forging or moulding and subsequent mechanical finishing machining, comprises an axial part FLA, which is substantially plane, and one or more radial expansions FLR.

The axial part FLA defines the abutment ring R described above, whereas the radial part defines the support for the brake caliper and for possible further components, such as for example the ABS sensor and/or the plate protecting the brake disc (not shown) .

The axial part FLA has an axial symmetry with a central hole, so as to be fitted on the bridge arm BA.

The radial part FLR, besides projecting radially, can also project according to the symmetry axis X of the axial part FLA, so as to protrude outwards towards the brake disc BD, so that, in the assembled operating condition of the flange FPR, the radial part slightly projects towards the brake disc, so as to move the fixing point of the relative caliper closer to it.

According to a method for the assembly of the bridge arm and, hence, of the wheel hub, the flange is welded on both the opposite axial faces of the relative axial part FLA and, subsequently, the contact face CF, which is the one intended to create the abutment surface for the fixed part BF of the bearing B, is ground, for example using a lathe .

According to a preferred embodiment of the invention, said contact face CF comprises three or more axial projections RS, preferably angularly evenly distributed.

The procedure used to weld the contact face CF to the bridge arm BA comprises adding material WM in the gap defined by two angularly consecutive projections RS . In this way, advantageously, the following grinding procedure only involves the projections RS .

Therefore, the presence of the projections allows manufacturers to avoid having to carry out a grinding procedure on the added weld material WM, which notoriously has physical and homogeneity features that make it harder to be processed compared to the properties of the material used to manufacture the flange FPR.

The non-limiting example described above can be subjected to variations, without for this reason going beyond the scope of protection of the invention, comprising all equivalent embodiments for a person skilled in the art.

When reading the description above, a skilled person can carry out the sub ect-matter of the invention without introducing further manufacturing details. The elements and features contained in the different preferred embodiments, drawings included, can be combined with one another, without for this reason going beyond the scope of protection of this patent application. The information contained in the part concerning the state of art only serves the purpose of better understanding the invention and does not represent a declaration of existence of the items described. Furthermore, if not specifically excluded by the detailed description, the information contained in the part concerning the state of art can be considered as combined with the features of the invention, thus forming an integral part of the invention. None of the features of the different variants is essential and, therefore, the single features of each preferred variant or drawing can be individually combined with the other variants.