FR3128932A1 - Mechanical reinforcement for the rear mounting bracket of an engine cradle - Google Patents

Abstract

The invention relates to a mechanical reinforcement for the rear mounting bracket of an engine cradle. According to the invention, the mechanical reinforcement (2) comprises an elongated piece (4) extending between a proximal end (6) and a distal end (8). The slender part (4) comprises first means for fixing the distal end (8) to a first support (24) for rear fixing of a motor cradle (26) and second means for fixing the proximal end ( 6) to a second rear attachment support (30) of the same engine cradle (26). The mechanical reinforcement thus limits the displacement of the rear mounting brackets of the engine subframe during a collision, in order to preserve the components of a vehicle located near the rear part of the engine subframe. (Figure 3)

Description

Mechanical reinforcement for the rear mounting bracket of an engine cradle

Technical field to which the invention relates

The invention relates to shock absorption at the front of a motor vehicle. More particularly, the invention relates to a vehicle front structure as well as to a vehicle capable of absorbing front shocks.

Technology background

A front shock absorption system or device for a vehicle conventionally consists of a transverse beam fixed to the front ends of stretchers via deformable sections. The side rails are two sections of the front structure of the vehicle extending in the extension of the floor of the vehicle towards the front compartment of the vehicle.

The front shock absorption system is also conventionally made up of the elements of the front compartment, located behind the transverse beam, such as the powertrain, the front axle, the engine cradle. These elements also participate in the absorption of the energy generated during an impact occurring at the front of the motor vehicle, by a stacking phenomenon. These elements, generally linked together and fixed to the side rails, contribute particularly in the event of front impacts at higher speeds, causing the power unit to recoil.

During a front impact, localized on only one side of the motor vehicle, it was found that the engine subframe was subjected to strong transverse mechanical stresses. These mechanical stresses are transmitted to the elements located close to the rear mounting brackets of the cradle, in particular at the level of the front tunnel of the motor vehicle. However, the flared and slender shape of the front tunnel located near the engine cradle, makes it particularly vulnerable to transverse stresses.

The invention aims to solve this technical problem, by proposing a mechanical reinforcement making it possible to increase the mechanical resistance of an engine cradle at the level of its rear part.

Object of the invention

To this end, the invention proposes a mechanical reinforcement intended to keep two rear mounting brackets of an engine cradle apart. The mechanical reinforcement is remarkable in that the mechanical reinforcement comprises an elongated part extending between a proximal end and a distal end, and in that the elongated part comprises first means for fixing the proximal end to a first support of rear fixing of an engine cradle and, second means for fixing the distal end to a second rear fixing support of the same engine cradle.

The mechanical reinforcement according to the invention is therefore configured to be maintained at the rear mounting brackets of an engine cradle, in order to maintain constant or substantially constant the distance between the rear mounting brackets of the engine cradle, when one of the rear attachment is subjected to a transverse stress due to a front impact, localized at a single side of a motor vehicle equipped with said engine cradle.

The mechanical reinforcement according to the invention thus limits the relative displacement of the rear mounting brackets between them during a collision, in order to preserve the elements of the motor vehicle located close to the rear part of the engine subframe, in particular the shape of the tunnel and elements present in said tunnel.

According to a variant embodiment, the slender piece is delimited by a first side wall facing a second side wall, and the side walls are connected by a third wall. Preferably, the first side wall is parallel or substantially parallel to the second side wall, so that in a plane transverse to the slender piece, the side walls and the third wall form a "U" or substantially a "U".

According to a variant embodiment, in a plane parallel or substantially parallel to the third wall, the proximal and distal ends are set back or slightly set back from the center of the slender part, and the proximal and distal ends are located on the same side of the slender piece. In other words, the slender piece can have a regular or irregular curvature along its length, so that the proximal and distal ends are set back from the center of the reinforcement.

According to a variant embodiment, the first fixing means and/or the second fixing means comprise a plate extending perpendicularly or substantially perpendicular to a side wall of the slender part, and the plate is crossed by at least one opening to allow the passage in part of a screw or a rivet. Preferably, at least one plate extends an edge of a side wall.

According to a variant embodiment, the slender part is made from a material with a very high elastic limit, preferably from a high-performance steel. By “very high elastic limit”, is meant a material characterized by an elastic limit greater than 400 MPa, preferably between 500 MPa and 700 MPa.

According to a variant embodiment, at least one wall of the slender part has a thickness equal to or greater than 1.5 mm, preferably between 1.5 mm and 3 mm.

According to a variant embodiment, the slender part can be made from a bent or stamped sheet, comprising fixing lugs intended to allow the slender part to be held in place on the rear fixing supports of an engine cradle, as described above.

According to another alternative embodiment, the slender part may comprise a fourth wall, opposite the third wall and connecting the side walls to each other, so as to form a tube of rectangular or substantially rectangular section. The slender piece can then be fixed directly to the rear fixing brackets by means of screws or similar means.

The invention also relates to an engine cradle for a motor vehicle, comprising a first rear fixing support and a second rear fixing support, the first rear fixing support is linked to a proximal end of a mechanical reinforcement as described above , and the second rear fixing support is connected to a distal end of said mechanical reinforcement.

According to a variant embodiment, the mechanical reinforcement is composed of a slender part delimited by a first side wall facing a second side wall, the side walls are connected by a third wall. Preferably, the third wall is parallel or substantially parallel to the engine cradle. Preferably, the third wall is perpendicular or substantially perpendicular to the first and to the second wall.

According to a preferred embodiment, the third wall is opposite the engine cradle.

The invention also relates to a motor vehicle comprising an engine cradle as described above.

Other advantages and characteristics may emerge more clearly from the description that follows.

Description of figures

The invention will be better understood on reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which:

represents a schematic and perspective view of a mechanical reinforcement according to the invention;

shows a schematic view of a cross section of a mechanical reinforcement according to the invention;

represents a schematic and partial view of a motor vehicle comprising an engine cradle equipped with a mechanical reinforcement as illustrated by the .

In these figures, the same references are used to designate the same elements.

Claims (10)

Mechanical reinforcement (2) intended to hold apart two rear mounting brackets of an engine cradle (26), characterized in that the mechanical reinforcement (2) comprises an elongated part (4) extending between a proximal end (6) and a distal end (8), and in that the slender part (4) comprises first means for fixing the distal end (8) to a first rear fixing support (24) of an engine cradle (26) and second means for fixing the proximal end (6) to a second rear fixing support (30) of the same engine cradle (26). Mechanical reinforcement (2) according to Claim 1, characterized in that the slender piece (4) is delimited by a first side wall (10) facing a second side wall (12), and in that the side walls (10, 12) are connected by a third wall (14). Mechanical reinforcement (2) according to Claim 2, characterized in that the first side wall (10) is parallel or substantially parallel to the second side wall (12), so that in a plane transverse to the slender piece (4), the side walls and the third wall (14) form a "U" or substantially a "U". Mechanical reinforcement (2) according to Claim 2 or 3, characterized in that in a plane parallel or substantially parallel to the third wall (14), the proximal and distal ends (6, 8) are set back or slightly set back from the center of the slender piece (4), and in that the proximal and distal ends (6, 8) are located on the same side (A) of the slender piece (4). Mechanical reinforcement device (2) according to one of Claims 2 to 4, characterized in that the first fixing means and/or the second fixing means comprises a plate (18) extending perpendicularly or substantially perpendicularly to a side wall (12) of the slender part (4), and in that the plate (18) is crossed by at least one opening (22) to allow the passage in part of a screw or a rivet (28). Mechanical reinforcement device (2) according to one of Claims 2 to 5, characterized in that at least one wall (10, 12, 14) of the elongated piece (4) has a thickness equal to or greater than 1.5 mm. Mechanical reinforcement device (2) according to one of Claims 1 to 6, characterized in that the slender part (4) is made from a material with a very high elastic limit. Engine cradle (26) for a motor vehicle, comprising a first rear attachment support (24) and a second rear attachment support (30), characterized in that the first rear attachment support (24) is linked to a proximal end ( 6) of a mechanical reinforcement (2) according to one of claims 1 to 7, and the second rear attachment support (30) is connected to a distal end (8) of said mechanical reinforcement (2). Engine cradle (26) for a motor vehicle, comprising a first rear attachment support (24) and a second rear attachment support (30), characterized in that the first rear attachment support (24) is linked to a proximal end ( 6) of a mechanical reinforcement (2) according to one of claims 2 to 6, and the second rear attachment support (30) is connected to a distal end (8) of said mechanical reinforcement (2), and in that the third wall (14) of said mechanical reinforcement (2) is opposite the engine cradle (26). Motor vehicle characterized in that it comprises an engine cradle (26) according to claim 8 or 9.