AXLE OBTAINED "

Scope of the invention

The present invention relates to the field of rear axles for land vehicles, and in particular industrial and commercial vehicles.

State of the art

Rear axles are generally made of two tubular elements, called axle arms, which extend from the central part, generally the differential, to the sides of the vehicle, i.e. the wheels. Each of the ends comprises connection elements to connect the brake calipers. Evidently, the end of the axle requires extremely precise machining at least to make the connection elements of the brake calipers.

The handling of said tubular elements is not particularly easy due to their longitudinal extension, so the operations are long and costly.

In some cases, the axle end comprises a tapered portion on which the wheel bearing is keyed externally. A fortiori the end needs to be turned to obtain a suitable support for the wheel bearing.

Today forming processes make it possible to obtain metal tubular elements which end with a sort of flat flange perpendicular to the axis of the tubular element machined, without performing any welding.

The extension of said flange, as a result of technological limitations or/and for savings of material, is very limited and is not sufficient to obtain a connection element for a brake caliper.

Summary of the invention

The purpose of the present invention is to implement a rolling process in the construction of a vehicular rear axle, so as to permit a significant reduction of costs.

The basic idea of the present invention is to make an auxiliary element of reduced axial dimensions comprising a connection element for the brake caliper and capable of supporting a wheel bearing.

In other words, the precision machining is all concentrated on said auxiliary element of small dimensions, while the axle arm is obtained by rolling and the relative small end flange is sufficient for the reciprocal connection of the axle arm end to the auxiliary element.

The present invention relates to a method of manufacturing a rear axle of a vehicle.

Another purpose of the present invention is a rear axle comprising an axle arm and an auxiliary element capable of supporting a wheel bearing and a connection element for a brake caliper.

A further purpose of the present invention is an industrial or commercial vehicle comprising the aforementioned rear axle.

The claims describe preferred variants of the invention, forming an integral part of the present description .

Brief description of the figures

Further purposes and advantages of the present invention will be clear from the detailed description below of an example of embodiment thereof (and of its variants) and from the appended drawings, provided merely by way of a non-limiting example, wherein:

Figure 1 shows a first axial cross-section of an example of embodiment of a rear axle according to the present invention,

Figure 2 shows a second axial cross-section of the example in Figure 1,

Figure 3 shows an enlargement of the axial cross- section in Figure 1,

Figure 4 shows an alternative variant to the embodiment shown in Figure 3.

Identical reference numerals and letters in the drawings refer to the same elements or components. In the present description the term "second" component does not imply the presence of a "first" component. These terms are in fact used only for clarity and are not intended as limiting .

Detailed description of embodiments

Figure 1 shows a longitudinal cross-section of a rear axle of an industrial or commercial vehicle according to the present invention. Figure 2 shows another axial cross- section, angularly displaced compared to the first, showing additional details attributable to the component AX described below.

The axle arm HB has a tubular shape and is made by rolling. In an end zone towards the wheel R, it comprises a flange F made in one piece with the same rolling process or by radial forging or upsetting of one end of the axle arm HB, and not by means of a separate manufacturing process of the flange and successive assembly/welding to the axle arm HB.

An auxiliary element AX, also called bearing support, has a bell shape, i.e. like an omega axial cross-section, and has a larger base FAX complementary to the aforementioned flange F to be connected thereto by means of the screws S arranged axially. In other words, the larger base FAX of the auxiliary element AX also defines a flange FAX complementary to the flange F of the axle arm HB .

The relative smaller base of the auxiliary element AX is open to allow the wheel hub H to fit axially inside the auxiliary element AX.

Said insertion causes the auxiliary element AX to be annular to the wheel hub H. As a result, an annular bearing B is arranged between the two, preferably formed of a pair of opposite conical bearings.

The wheel hub H is a tapered shape towards the first end part HI. The end part H2, opposite the tapered part HI, widens radially to support the brake disc BD and wheel rim R. The inner end part HI, tapered, comprises a threaded area suitable to be coupled to a corresponding locking nut G. This locking nut axially locks the bearing B, sandwiched between the wheel hub H and the bearing support AX.

As a result, once the wheel hub H has been inserted in the auxiliary element AX, with the bearing B annularly interposed, the nut G makes these three elements AX/B/H a single body, wherein the wheel hub H is rotatably joined to the auxiliary element AX along the axis X.

The auxiliary element, or bearing support AX comprises a radial support element BS, see Figure 1, which projects radially for a narrow angular portion in order to support the brake caliper BP. Figure 2, instead, shows a screw SI which locks the brake caliper BP to the bearing support AX.

Other angular portions, appropriately staggered and possibly equally spaced from one another at an angle may be provided for. For example, an angular portion SP1 is defined to support a possible protective disc PD generally connected in a parallel position to the brake disc to protect it from dust and from spurts of water.

The auxiliary element AX may further comprise an additional radial portion, see Figure 1, which projects radially in another angular direction to make the support of an ABS sensor possible.

According to the variant shown in the figures it may be seen that the speed sensor is made directly on a portion of the brake disc BD, but it may also be made on the wheel hub H, if properly shaped.

The outer end portion H2 of the wheel hub H widens radially to define a circular support flange, to support the brake disc BD and said wheel rim R.

The brake disc is in the standard shape, which is in itself known, and in the operating condition, its lower base is inserted to form a sandwich, between the end H2 of the wheel hub H and the rim R.

It is clear to see that there are strong similarities between the shape of the brake disc BD and the auxiliary element AX, both being bell-shaped with an open lower base. The wheel hub H may be solid or axially hollow or partially hollow .

In relation to the fact that the axle may be a drive axle or not, a drive shaft TR may be arranged inside the axle arm, along the extension axis X, with one end securely fastened rotatably to the inner end HI of the wheel hub H. A coupling suitable for said purpose may provide for a grooved profile both in the end of the drive shaft TR and in a complementary coaxial cavity defined at least in the inner end HI of the wheel hub H.

From the description provided here it is evident that the wheel hub H and the brake disc BD are axially symmetric. Instead, the auxiliary element AX may have an axial or partially axial symmetry excluding the radial portions

- SP2 supporting the brake caliper,

- supporting the ABS sensor and

- SP1 supporting the protection plate.

Figure 3 shows an enlargement of a part of Figure 1.

In the coupling part between the flange F and the larger base FAX of the component AX, a circumferential seat is made to house a gasket 0.

In addition, both the flange F and the larger base FAX of the component AX may comprise machining operations permitting a self-centering shape coupling, generically referred to as ACT. Such machining may or may not be annular, or affect only angular portions of the aforesaid parts.

According to a preferred variant of the invention, not mandatory, shown in Figure 4, the axle arm HB, at the flange F, comprises a circumferential ridge CR which projects axially to insert itself in the cavity defined by the smaller base of the bell-shaped component AX.

Said ridge is preferably made at the mouth of the inner cavity of the axle arm HB. Correspondingly, a circumferential seat complementary to said ridge CR is made on the flange FAX of the auxiliary element AX.

The ridge CR can be obtained either during the aforesaid rolling process and possibly finished with a turning process or can be obtained entirely by turning of the flange F.

Preferably, the circumferential seat in the auxiliary element AX comprises a seat for a circumferential gasket 0.

Advantageously, according to the present invention, the elements requiring high-precision construction are transferred, i.e.

- the brake caliper support,

- the support for the ABS sensor, where present, and

the seat of the bearing B of the wheel hub H, onto the auxiliary element AX, while the axle arm is made by means of a simple process that involves large tolerances, which do not affect the functioning of the final assembly.

Where a circumferential ridge CR is present with its seat made in the perimeter wall of the cavity, at its larger base, a turning process simple to implement is required that does not require high levels of accuracy.

Furthermore, the fact that the elements requiring greater precision are housed on the auxiliary element AX, and considering that said element AX has small axial dimensions, it is evident that the handling of the parts during the relative machining is made much simpler.

In particular, the machining operations of the component AX essentially comprise a first forging or casting of the component, which is subsequently turned, drilled and generally machined with precision techniques.

From the above description a person skilled in the art may make the object of the invention without introducing any further construction details. The elements and features shown in the various preferred embodiments may be combined while remaining within the scope of protection of the present application. The content of the description of the state of the art, unless specifically excluded in the detailed description, should be considered in combination with the features of the present invention, forming an integral part of the present invention .