Patent Description:
The invention relates to a front frame assembly comprising a suspension attachment structure for a motor vehicle.

As it is known, the front portion of the frame of motor vehicles has both a supporting function for supporting body elements and an absorption function for absorbing front crashes, namely those crashes taking place along the forward moving direction of the motor vehicle.

In particular, in order to absorb front crashes, the frame includes an absorption structure - known as "crash box" - which includes a pair of collapsible elements extending parallel to the longitudinal direction of the vehicle.

Said collapsible elements - for example in the form of extruded aluminium elements - are deformable along the forward moving direction of the vehicle relative to compression stresses. In detail, in response to a front crash, said collapsible elements deform, absorbing the energy of the crash, and the speed of the motor vehicle progressively becomes zero, namely according to a deceleration defined during the designing phase.

Generally speaking, the ability of the collapsible elements to absorb crashes is proportional to their length along the longitudinal direction of the vehicle. Therefore, the absorption of front crashes by the collapsible elements is correlated with the front projection of the vehicle, namely the distance between the front end of the vehicle and the axis of the front wheels along the longitudinal direction of the vehicle.

In motor vehicles with a heat engine arranged at the front, the front portion has dimensions that are sufficient to accommodate the heat engine. As a consequence, the front projection generally is such as to allow for the installation of collapsible elements that are long enough to effectively absorb front crashes.

However, in electric motor vehicles or in motor vehicles provided with a heat engine arranged at the back, for example in some sports cars, the front projection mostly is smaller than the one of motor vehicles provided with a heat engine arranged at the front.

In motor vehicles characterized by a small-sized front projection, the length of the collapsible elements is very limited and is not always sufficient to allow for an efficient absorption of front crashes. In addition, the extension of said elements is limited by the presence of a structure known as "shock tower", which is designed to accommodate the attachments of the suspensions of the motor vehicle and from which the collapsible elements extend.

The shock tower is typically obtained by means of casting processes. As a consequence, due to the defects and to the normally weaker mechanical features of casting products compared to components obtained by means of other process, it is hard to foresee the tensile strength behaviour of the shock tower.

Owing to the above, known motor vehicles need to be improved in order to efficiently foresee their ability to absorb front crashes.

The object of the invention is to fulfil the need discussed above, preferably in a simple and reliable fashion.

<CIT> discloses a front side frame, the rear end of which is fixed to a front face of a dashboard lower panel of a vehicle body formed into a bathtub shape, includes a fixed portion, an inclined portion, a bent portion and a horizontal portion. In addition, when the collision load of a frontal collision is input into the front end of the front side frame, the fixed portion and the bent portion buckle so as to bend back, and the upper face of the inclined part abuts against the front face of the dashboard lower panel, thus not only making it possible to absorb the collision energy by deformation of the front side frame itself, and to increase the area over which the load is transmitted from the front side frame to the dashboard lower panel to thus disperse the load, thereby reducing the reaction force required for the dashboard lower panel.

Said object is reached by a front frame assembly for a motor vehicle as defined in claim <NUM>.

The dependent claims define special embodiments of the invention.

Hereinafter, an embodiment of the invention will be described, in order to allow the latter to be better understood, by way of non-limiting example and with reference to the accompanying drawings, wherein:.

In <FIG>, reference number <NUM> is used to indicate, as a whole, a motor vehicle comprising:.

The passenger compartment, the suspensions and the steering system are known and, therefore, are not shown and described in detail hereinafter.

The vehicle <NUM> further comprises a front portion 1a and a rear portion 1b with respect to a forward moving direction A of the vehicle <NUM>. The vehicle <NUM> also defines a longitudinal direction X, with respect to which the front portion 1a and the rear portion 1b are opposite one another.

In particular, the frame <NUM> comprises:.

The body cell <NUM> comprises, in turn, a floor board 10a oriented perpendicularly or substantially perpendicularly to the direction Z and extending between the front portion 1a and the rear portion 1b along the longitudinal direction X.

Without this implying any lack of generality, the vehicle <NUM> comprises a first electric motor at the front portion 1a, a second electric motor at the rear portion 1b and one or more batteries interposed between the first and the second motor along the longitudinal direction X and arranged under the floorboard 10a. The first motor, the second motor and the battery are known and, therefore, are not shown and described in detail hereinafter.

More precisely, the assembly <NUM> comprises two structures <NUM> arranged at respective ends of the body cell <NUM> according to a direction Y orthogonal to the longitudinal direction X and to the direction Z. The structures <NUM> are parallel to one another and to the longitudinal direction X (<FIG>).

The structures <NUM> project relative to the body cell <NUM> and, in particular, directly from the body cell <NUM>.

The structures <NUM> preferably are identical to one another. For this reason, the description below will only disclose in detail one of the structures <NUM>, provided that each feature described for one of the structures <NUM> also applies to the other structure <NUM>.

The structures <NUM>, if necessary, could also be considered or manufactured as one single structure <NUM>.

In the specific case shown herein, the structure <NUM> comprises (<FIG>):.

The structure <NUM> also comprises two surfaces 12d, 12e opposite one another along the direction Z and interposed between the surface 12b and the surface 12c along the direction X. In addition, the surface 12d and the surface 12e are interposed between the planar surfaces 12a along the direction Y.

In detail, the surface 12d is flat and closer to the ground than the surface 12e along the direction Z. In other words, the surface 12b is arranged under the surface 12e.

In particular, the attachment portion <NUM> is arranged at the surface 12c.

The structure <NUM> or, better said, each one of the structures <NUM> can preferably be manufactured as one single piece, for instance manufactured by means of a casting technique.

The structure <NUM> further comprises a through opening <NUM> parallel to the direction Y. Said opening <NUM> is adapted to be passed through by a component of the steering system, for example a steering tie rod.

In the specific case shown herein, the opening <NUM> has a polygonal shape and is obtained at the planar surfaces 12a.

Furthermore, the structure <NUM> is at least indirectly connected to the first electric motor, so that a deformation of the structure <NUM> corresponds to a shift of the first motor relative to the second motor.

As shown in <FIG> and <FIG>, the assembly <NUM> comprises an absorption element <NUM> and an absorption element <NUM> at each structure <NUM>.

In detail, the absorption elements <NUM>, <NUM> each comprise an extruded element, namely a box-like element, extending parallel to the longitudinal direction X. Hereinafter, reference will be made to one single absorption element <NUM> and to one single absorption element <NUM>, since the absorption elements <NUM> are identical to one another, like the absorption elements <NUM>.

The element <NUM> and the element <NUM> associated with a same structure <NUM> are parallel to one another and to the longitudinal direction X and are spaced apart from one another parallel to the direction Z. In detail, the element <NUM> and the element <NUM> are aligned with one another along the direction Y. More in detail, the element <NUM> is arranged above the element <NUM>, so that the element <NUM> is closer to the ground along the direction Z during the use of the vehicle <NUM>.

Furthermore, the element <NUM> and the element <NUM> are distinct from the structure <NUM> and are fixed thereto.

The element <NUM> and the element <NUM> extend starting from the structure <NUM>, namely project relative to the structure <NUM>. In detail, the elements <NUM> and <NUM> directly project from the structure <NUM> on the side opposite the attachment portion <NUM>. More in detail, the elements <NUM> and <NUM> extend starting from different portions of the structure <NUM> at the surface 12b.

In the specific case shown herein, the cross section of the element <NUM> parallel to the longitudinal direction X is larger than the cross section of the element <NUM> parallel to the longitudinal direction X.

The absorption elements <NUM> and <NUM> are preferably obtained by means of a mechanical extrusion process.

The assembly <NUM> further comprises an absorption assembly <NUM> for the absorption of front crashes of the motor vehicle <NUM> extending transversely to the absorption elements <NUM> and <NUM> (<FIG> and <FIG>).

The assembly <NUM> has two ends 18a, 18b along the direction Y, which are fixed to the elements <NUM> and <NUM>, respectively, at corresponding ends thereof, which are opposite relative to the structures <NUM> along the longitudinal direction X.

In the specific case shown herein, the absorption assembly <NUM> comprises (<FIG>):.

The absorption assembly <NUM> further comprises two planar elements <NUM>, <NUM> extending parallel to the direction Z and each arranged at a respective end of the cross members <NUM> and <NUM> along the direction Y. In other words, the cross members <NUM>, <NUM> and the elements <NUM>, <NUM> define a body with a rectangular shape.

The absorption assembly <NUM> can also comprise two reinforcement elements <NUM> arranged diagonally relative to the cross members <NUM>, <NUM> and to the elements <NUM>, <NUM>. Said reinforcement elements <NUM> extend at the space portion delimited by the cross members <NUM> and <NUM> and by the elements <NUM> and <NUM> (<FIG>).

The assembly <NUM> also comprises a cross member <NUM> arranged parallel to the direction Y between the two structures <NUM>. Said cross member <NUM> is parallel to the cross members <NUM> and <NUM> and is spaced apart from them along the longitudinal direction X.

Each structure <NUM> advantageously comprises an opening <NUM> with an elongated shape along a direction B, which is transversal to the directions X and Y, and a further opening <NUM> opposite the opening <NUM> relative to the opening <NUM>. In detail, the opening <NUM> is arranged on the side of the surface 12e and the opening <NUM> is arranged on the side of the surface 12d relative to the opening <NUM>.

The opening <NUM> and the opening <NUM> allow mechanical stresses to be concentrated. More in detail, the structure <NUM> comprises a collapsible region <NUM> interposed between the opening <NUM> and the opening <NUM> and a collapsible region <NUM> interposed between the opening <NUM> and the surface 12d and/or between the opening <NUM> and the opening <NUM> (<FIG> and <FIG>). In detail, the term "collapsible" is meant in a relative manner with respect to the attachment portion <NUM>, in particular meaning more collapsible than the attachment portion <NUM>. The collapsible regions <NUM> and <NUM> comprise part of the planar surfaces 12a.

The orientation of the opening <NUM> allows the mechanical behaviour of the structure <NUM> to be guided, thus supporting the deformation in a preferential deformation direction.

Specifically, the direction B is parallel to the planer surfaces 12a.

Moving along the direction X from the side surface 12b to the side surface 12c, namely in the direction oriented from the front portion 1a to the rear portion 1b, the opening <NUM> comprises, one after the other, a first end 30a and a second end 30b opposite one another along the direction B. In detail, the distance of the first end 30a from the surface 12d is greater than the distance of the second end 30b from the surface 12d. In other words, the angle formed between the direction B and the longitudinal direction X on the side of the surface 12b, namely on the side of the front portion 1a, is acute.

More in detail, the structure <NUM> comprises surfaces <NUM> and <NUM>, which extend between the planar surfaces 12a and define the opening <NUM> and the opening <NUM>, respectively. Said surfaces <NUM> and <NUM> are cylindrical and are oriented parallel to the direction Y.

The opening <NUM> is preferably shaped like a buttonhole. Furthermore, in the embodiment shown herein, though not necessarily, the opening <NUM> comprises a rib <NUM> interposed between the first end 30a and the second end 30b along the direction B.

The rib <NUM> is oriented in an oblique manner relative to the direction X.

The opening <NUM> is a hole delimited by a cylindrical surface. The generatrix line of said cylindrical surface is preferably oriented transversally to the direction Y. This allows the deformability of the structure <NUM> to be controlled.

In use, in case of a front crash, the assembly <NUM> deforms so as to absorb the energy associated with the crash and in order to limit the deceleration of the vehicle <NUM> as much as possible. In detail, the elements <NUM> and <NUM> are compressed along the longitudinal direction X and, subsequently, the structure <NUM> deforms as well. More in detail, the structure <NUM> starts deforming from the collapsible regions <NUM> and <NUM>.

The deformation of the structure <NUM> determines the shift of the first motor relative to the second motor. In detail, the first motor rigidly rotates around an axis of its own, which is parallel to the direction Y.

Owing to the above, the advantages of the assembly <NUM> according to the invention are evident.

Since the structure <NUM> comprises the opening <NUM>, which is elongated along the direction B, and the opening <NUM>, which is opposite the opening <NUM> relative to the opening <NUM>, it is possible to foresee, with a high degree of likelihood, the tensile strength behaviour of the structure <NUM>, which is generally obtained by means of casting processes. This allows the assembly <NUM> to absorb front crashes in an effective and repeatable manner and, at the same time, limits the front projection of the vehicle. As a matter of fact, the openings <NUM> and <NUM> define the collapsible regions <NUM> and <NUM>, which constitute the points from which the yielding of the structure <NUM> is most likely to start in case a front crash.

In addition, since the structure <NUM> is at least indirectly connected to the first electric motor, in case of a front crash, the first motor rigidly rotates around an axis of its own, which is parallel to the direction Y. This reduces the translation of the first motor towards the second motor along the longitudinal direction X and limits the risk for the first motor of hitting the battery.

Finally, the assembly <NUM> according to the invention can clearly be subjected to changes and variants, which, though, do not go beyond the scope of protection defined by the appended claims.

The motor vehicle <NUM> could be a vehicle provided with a heat engine on the side of the rear portion 1b, for example a sports car.

In particular, the number and the shape of the components described and shown herein could be different and, in particular, could be changed with a great degree of freedom. More in particular, the assembly <NUM> could comprise one single structure <NUM> or more than two structures <NUM> and one single absorption element <NUM>, <NUM> or more than two absorption elements <NUM>, <NUM>.

Claim 1:
Front frame assembly (<NUM>) for a motor vehicle (<NUM>) comprising:
- at least one suspension attachment structure (<NUM>) connectable to a body cell (<NUM>) of said motor vehicle (<NUM>); said body cell (<NUM>) defining a passenger compartment of said motor vehicle (<NUM>); and
- at least one absorption element (<NUM>, <NUM>) adapted to absorb the energy associated with a front crash of said motor vehicle (<NUM>); said absorption element (<NUM>, <NUM>) being distinct from said structure (<NUM>), fixed with respect to said structure (<NUM>), and extending along a first direction (X) ;
said structure (<NUM>) comprising a first opening (<NUM>) adapted to be passed through by a component of a steering system of said motor vehicle (<NUM>);
characterized in that said structure (<NUM>) further comprises:
- a second opening (<NUM>) having an elongated shape along a second direction (B) transversal to said first direction (X); and
- at least one third opening (<NUM>) opposite said second opening (<NUM>) with respect to said first opening (<NUM>) .