Patent Description:
Heavy vehicles, such as trucks or buses, are knowingly provided with wheels, which have a fixed camber angle relative to the ground.

The camber angle is the angle between the vertical and the middle plane of the wheel when viewed from the front. If the top of the wheel is farther out than the bottom, it is called positive camber, vice versa it is called negative camber.

A change in said angle affects the driving performance of the vehicle and, especially in case of a heavy vehicle, the wear of the tyres, thus changing their surface in contact with the ground.

Based on current environmental needs, there is a stronger and stronger need to provide vehicles with an improved driving performance and to reduce the wear of the elements making them up, such as tyres.

Known wheel assemblies are disclosed in published documents <CIT>, <CIT>, <CIT>, <CIT> or <CIT>.

The object of the invention is to fulfil the needs discussed above in an optimized and economic fashion.

The aforesaid object is reached by a wheel assembly comprising a camber angle adjustment device and by a vehicle comprising said wheel assembly as claimed in the appended independent claims.

Further preferred embodiments of the invention are described in the dependent claims or in the claims connected to the aforesaid independent claims.

The invention will be best understood upon perusal of the following detailed description of a preferred embodiment, which is provided by way of non-limiting example, with reference to the accompanying drawings, wherein:.

<FIG> shows a known wheel assembly <NUM> comprising a wheel <NUM> for a heavy vehicle, which is not shown. In particular, the wheel <NUM> comprises a disc 2a, which is mounted so as to freely rotate on a hub <NUM>, and a rim 2b, which is rigidly carried by the disc 2a and defines a support for a tyre <NUM>.

In the case described herein, since it relates to a heavy vehicle, the hub <NUM> is carried by an axle <NUM> and is advantageously defined by a knuckle <NUM>, which is connected to the axle <NUM> in a movable manner, as defined hereinafter.

The knuckle <NUM> can have any shape and is configured to define a plurality of anchoring points <NUM> for elements of the vehicle configured to control the steering of the wheel <NUM>, namely its inclination relative to a longitudinal axis of the vehicle, as well as for elements of the suspension system of the vehicle configured to connect the knuckle <NUM> and/or the axle <NUM> to the frame of the vehicle.

In particular, the knuckle <NUM> comprises a main body <NUM> defining the aforesaid anchoring points <NUM> and specifically comprising an upper portion 8a, a lower portion 8n and an intermediate portion 8c, which connects the upper and lower portions 8a, 8b. Preferably, the upper portion 8a and the lower portion 8b of the main body <NUM> are arranged on opposite end sides of the intermediate portion 8c and project from it, in particular on the opposite side relative to the hub <NUM>. According to the embodiment shown herein, the anchoring portions <NUM> are defined by the upper and lower portions 8a, 8b and, according to <FIG>, the upper and lower portions 8a, 8b preferably have a substantially "C"-shaped cross section. Advantageously, the main body <NUM> is manufactured as one single piece.

The knuckle <NUM> is connected to the axle <NUM> through a pin <NUM> comprising an upper end portion 9a, which is fixed to the upper portion 8a, and a lower end portion 9b, which is fixed to the lower portion 8b.

The pin <NUM> advantageously has a prismatic shape, which is substantially cylindrical and constant between the upper and lower portions 9a, 9b, and extends along an axis A. Said pin <NUM> is housed inside a respective seat <NUM>, which is obtained in the axle <NUM> and is sized so as to allow the pin <NUM> to rotate around the axis A.

Based on the configuration described above, the axis A is the steering axis of the wheel <NUM> and the steering can the operated by the aforesaid elements, which act by applying a force in the anchoring portions <NUM>.

According to the invention, the wheel assembly <NUM> comprises an adjustment device, which is configured to change the inclination of the axis of the pin <NUM> relative to the vertical. Preferably, this variation relative to the vertical can be a variation in a transverse plane of the vehicle (camber angle).

The adjustment device <NUM> basically comprises:.

Advantageously, the thrust element <NUM> comprises a threaded element <NUM>, which is housed in a respective seat <NUM> obtained on the axle <NUM> and comprises a contact portion 15a, which is configured to cooperate in contact with the pin <NUM>, and an adjustment portion 15b on the opposite side relative to the contact portion 15a with respect to the seat <NUM>.

The threaded element <NUM> is configured to cooperate with a respective thread obtained in the seat <NUM> so that a rotation thereof turns into an extension or retraction along its longitudinal axis. Preferably, the threaded element <NUM> is a screw and the adjustment portion 15b comprises a nut <NUM>, which is configured to facilitate the movement of the screw along the aforesaid longitudinal axis.

The contact portion 15a, as mentioned above, cooperates in contact with the pin <NUM> and, preferably, in a seat <NUM>' obtained in the latter and configured to have a shape corresponding to the one of the contact portion 15a.

The support element <NUM> with different degrees of freedom advantageously comprises a ball joint <NUM>. Advantageously, the ball joint <NUM> is carried in a rotary manner, for example by means of rolling means <NUM>, by the lower portion 8b of the main body <NUM> of the knuckle <NUM> and defines a through opening <NUM>, which is configured to house the pin <NUM>.

Advantageously, the ball joint <NUM> comprises a spherical portion <NUM>, which has a centre O, which is part of the rotation axis A o the pint <NUM>. The spherical portion <NUM> defines an outer contact surface, which is configured to cooperate with a respective seat <NUM> with a complementary shape obtained on the axle <NUM>. Advantageously, said seat <NUM> communicates with the seat <NUM> housing the pin <NUM>.

According to the description above, the seat <NUM> has a flared shape, which, in particular, tends to widen crosswise to the axis A from the lower portion 9b to the upper portion <NUM>.

The opening of the seat ranges from plus to minus <NUM>° relative to the neutral portion of the axis A corresponding to the neutral position (namely, with <NUM>° camber angle) of the wheel <NUM>.

As a consequence, the pin <NUM> can move by plus or minus <NUM>° relative to the axis A.

Advantageously, the adjustment device <NUM> can comprise a second thrust element <NUM>, which is configured to cooperate in contact with the pin <NUM> on the opposite side relative to the first thrust element <NUM>.

Preferably, the second thrust element <NUM> comprises a cam <NUM>, which is configured to define a contact surface for the pin <NUM>. The position of the cam <NUM> can be adjusted depending on the movement of the first thrust element <NUM>.

In particular, the position of the cam <NUM> is adjusted by means of threaded means <NUM>, which are advantageously manufactured as one single piece together with the cam <NUM> and are configured to be engaged in a hole <NUM> made on the axle <NUM>. Similarly to the first thrust element <NUM>, the threaded means <NUM> comprise a screw <NUM> configured to engage the hole <NUM> and a nut <NUM> to allow it to move along its longitudinal axis.

As <FIG> clearly reveals, the longitudinal movement axes of the first and of the second thrust element <NUM>, <NUM> are incident and coplanar to one another and, more advantageously, perpendicular.

The embodiment of the wheel assembly <NUM> comprising an adjustment device <NUM> according to the invention, as described above, works as follows.

<FIG> show condition in which the position of the axis A of pin <NUM> is inclined relative to the vertical so as to obtain a neutral camber angle condition.

<FIG>, <FIG> show a condition of extreme position of the axis A of the pin <NUM>, in which a negative camber angle α relative to the condition of <FIG> is maximized.

In order to reach the condition of <FIG>, according to <FIG>, the nut <NUM> simply needs to be rotated so that the screw <NUM> tends to move removing itself from the respective seat <NUM>. At the same time, by rotating the nut <NUM>, the cam <NUM> can be moved so that its profile remains in contact with the pin <NUM>, hence laterally supporting the latter.

The movement of the pin <NUM> is followed by the ball joint <NUM>, whose spherical portion <NUM> cooperates in contact with the relative seat <NUM>. Once the angle α is set, thanks to the rolling means <NUM>, the ball joint <NUM> can rotate around the axis A, thus allowing for the steering of the wheel assembly <NUM>.

<FIG>, <FIG> show a condition of extreme position of the axis A of the pin <NUM>, in which a positive camber angle β relative to the condition of <FIG> is maximized.

In order to reach the condition of <FIG>, according to <FIG>, the nut <NUM> simply needs to be rotated so that the screw <NUM> tends to move inserting itself into the respective seat <NUM>. At the same time, by rotating the nut <NUM>, the cam <NUM> can be moved so that its profile allows the pin <NUM> to move, at the same time laterally supporting the latter.

Also in this case, the movement of the pin <NUM> is followed by the ball joint <NUM>, whose spherical portion <NUM> cooperates in contact with the relative seat <NUM>. Once the angle β is set, thanks to the rolling means <NUM>, the ball joint <NUM> can rotate around the axis A, thus allowing for the steering of the wheel assembly <NUM>.

In case users need to set an intermediate camber angle between the two extreme conditions described above, a combined adjustment of the thrust elements <NUM> and <NUM> needs to be performed.

By providing sensor means to detect the camber angle of the wheel <NUM> and actuator means to move the thrust elements <NUM> and <NUM>, this operation can be automated, also providing an electronic unit configured to detect the camber angle of the wheel <NUM> and to control the actuator means accordingly, for example in a closed loop, until the desired camber angle is obtained.

Owing to the above, the advantages of a wheel assembly according to the invention are evident.

Thanks to the adjustment device <NUM> according to the invention, the angle of inclination of the knuckle <NUM> can be adjusted also in heavy vehicles.

Hence, the camber angle can be adjusted, thus significantly reducing the wear of the tyres and, hence, increasing the useful life thereof and reducing the consumptions of the vehicle.

The use of threaded means as thrust elements <NUM>, <NUM> allows for a precise adjustment of the pin <NUM> of the knuckle and, at the same time, for an effective connection to the axle. Furthermore, the system is very compact and can potentially be used in any vehicle, though basically not affecting the technical specifications of the other functional elements of the vehicle, such as the suspensions or the steering system. Finally, the wheel assembly according to the invention can be subjected to changes and variants, which, though, do not go beyond the scope of protection set forth in the appended claims.

For example, the thrust elements <NUM>, <NUM> described above could clearly be moved in a different manner. Furthermore, the shape of the knuckle <NUM> or of the axle <NUM> can evidently change and there can be further elements (suspensions, steering wheel) other than the ones described and shown herein by way of example.

Claim 1:
Wheel assembly (<NUM>) for a heavy vehicle comprising a wheel (<NUM>) and a hub (<NUM>) defined by a knuckle (<NUM>) configured to be carried by an axle (<NUM>) of said vehicle, said wheel (<NUM>)) being carried in a rotationally free way on said hub (<NUM>) and defining an angle (α, β) between an axis of incidence on the ground of said wheel with respect to a center line of the same,
said knuckle (<NUM>) being connected to said axle (<NUM>) by means of a pin (<NUM>) rigidly connecting two portions (8a, 8b) of said knuckle (<NUM>), said pin (<NUM>) extending along a longitudinal axis (A) and being rotationally free housed in a hole (<NUM>) passing through said axle (<NUM>),
said wheel assembly (<NUM>) including an adjustment device (<NUM>) to vary the inclination of said axis (A) of said pin (<NUM>) so as to vary said angle (α, β), characterized in that said adjustment device (<NUM>) comprises:
• a first thrust element (<NUM>) configured to vary the position of one of an upper or lower portion (9a, 9b) of said pin (<NUM>); and
• a support element (<NUM>) with multiple degrees of freedom to support the other between said upper or lower portion (9a, 9b).