Rear structure of a motor vehicle

Abstract

A motor vehicle rear structure includes an underframe component to support a motor vehicle floor and in which a tunnel is formed, an axle component including a central part and two lateral parts that define a space to accommodate a component of the vehicle, an articulation device including a first articulation element and a second articulation element which are able to pivot relative to one another, and at least one front reinforcing element fixed to the second articulation element and to the tunnel. The rear structure is arranged in such a way that said at least one front reinforcing element allows at least some of a load in the direction of travel of the motor vehicle derived from the axle component to be transmitted to the tunnel.

Claims

1. A motor vehicle rear structure, comprising: an underframe component to support a motor vehicle floor and in which a tunnel is formed; an axle component comprising a central part and, on each side of the central part, two lateral parts defining, with the central part, a space to accommodate a component of the vehicle; an articulation device comprising a first articulation element and a second articulation element which are able to pivot relative to one another, the first articulation element being fixed to or integrated into the central part of the axle component and the second articulation element being fixed to or integrated into the underframe component, the rear structure being arranged in such a way that the first and second articulation elements are able to pivot relative to one another about an axis that is substantially horizontal and substantially perpendicular to a direction of travel of the vehicle in a frame of reference of the motor vehicle, when the first and second articulation elements are thus fixed to or integrated into the central part of the axle component and to the underframe component of the motor vehicle, respectively; and at least one front reinforcing element fixed to the second articulation element and to the tunnel, the rear structure being arranged in such a way that said at least one front reinforcing element allows at least some of a load in the direction of travel of the motor vehicle derived from the axle component to be transmitted to the tunnel.

2. The motor vehicle rear structure as claimed in claim 1, in which the vehicle component accommodated in the space defined by the axle component comprises a rear engine.

3. The motor vehicle rear structure as claimed in claim 1, in which the second articulation element is directly fixed to or integrated into the underframe component.

4. The motor vehicle rear structure as claimed in claim 3, in which the second articulation element comprises two flanges integrated into the underframe component.

5. The motor vehicle rear structure as claimed in claim 1, in which said at least one front reinforcing element is obtained by pressing.

6. The motor vehicle rear structure as claimed in claim 1, in which the second articulation element and the front reinforcing element are arranged relative to one another so that they are substantially aligned in the direction of travel of the vehicle.

7. The motor vehicle rear structure as claimed in claim 1, further comprising at least one rear reinforcing element fixed to the second articulation element and to the underframe component, the rear structure being arranged so that said at least one rear reinforcing element allows at least some of a vertical load derived from the axle component to be transmitted to the underframe component.

8. The motor vehicle rear structure as claimed in claim 7, in which the rear reinforcing element and the second articulation element are arranged relative to one another so that they are substantially aligned in the vertical direction in the frame of reference of the vehicle.

9. A motor vehicle, comprising: the motor vehicle rear structure as claimed in claim 1.

Description

(1) The invention will be better understood with reference to the figures which illustrate embodiments given by way of nonlimiting example.

(2) FIG. 1 is a perspective view of the rear part of a motor vehicle according to one embodiment, some components, notably the rear axle component, not having been depicted.

(3) FIG. 2 is a perspective view of a portion of rear structure according to the embodiment of FIG. 1, certain components not having been depicted.

(4) FIG. 3 is a perspective view of part of a rear structure according to one embodiment of the invention.

(5) FIG. 4 is a perspective view in cross section, along the axis y, of part of a rear structure, according to one embodiment of the invention.

(6) From one figure to another, identical references will be used to denote elements that are identical or similar in shape or in function.

(7) In the present application, the axes x, y, z are the axes conventionally used in the automotive field, considered in the frame of reference of the motor vehicle, which means to say that the axis x is the front-rear axis of the vehicle, corresponding to the direction of travel when the steering wheel is straight, that the axis z is colinear with the gravity vector and of opposite sense to this gravity vector when the vehicle is standing with its wheels on flat ground, and that the axis y, or lateral axis, is perpendicular to the axes x and z, the axes x, y, z forming an orthonormal frame of reference.

(8) With reference to FIG. 1, a motor vehicle 1 comprises an underframe component 3 in which a tunnel 2 is formed.

(9) The underframe component 3 comprises an underframe part 39, in which the tunnel 2 is formed, and two flanges 31, 32 welded to the underframe part 39.

(10) These flanges 31, 32 are obtained from sheet metal, by pressing.

(11) These flanges 31, 32 define two recesses 35, 36 facing one another and intended to accommodate a rod (not depicted) on which a ring (not depicted) secured to another ring (not depicted) is rotationally mounted, this other ring being mounted, rigidly or with the ability to rotate, on a central part of a central-fixing axle component which has not been depicted. The component (not depicted) incorporating these two rings forms a first articulation element.

(12) The rod is rigid relative to the flanges 31, 32 and with these flanges forms a second articulation element. The second articulation element is therefore made in multiple components.

(13) The first and second articulation elements are thus able to pivot relative to one another about an axis that is parallel or substantially parallel to the axis y of the vehicle.

(14) The first articulation element is fixed to the axle component, not depicted, for example a de Dion axle, this axle component comprising a central part thus mounted articulated to the flanges 31, 32 and, on each side of this central part, two lateral parts. This axle component thus defines a space 4 to accept a propulsion engine, not depicted.

(15) The flanges 31, 32 form, with the rod and the rings, an articulation device between the de Dion axle and the underframe component 3.

(16) This articulation device allows pivoting about the axis y, this pivoting being depicted by the arrow 100.

(17) In this embodiment, the articulation device is thus configured so that the de Dion axle is rotationally mounted directly on the underframe component 3, without a cradle.

(18) The underframe component 3 therefore absorbs load derived from the de Dion axle, particularly load derived from the engine.

(19) The flanges 31, 32 define two additional recesses 37, 38 to accommodate an additional rod (not depicted) on which an engine torque reacting link rod (not depicted) is mounted.

(20) The flanges 31, 32 thus absorb a proportion of the load emanating from the engine.

(21) The articulation device and the central part of the de Dion axle component thus constitute a relatively heavily loaded zone forming both a bearing for rotation in y and a support for transmitting other loadings, notably load along the axis x and/or the axis z, particularly in the event of a frontal impact.

(22) Front reinforcing elements 51, 52 allow at least some of this load to be absorbed better. These front reinforcing elements 51, 52 are obtained from a metal sheet created by pressing.

(23) These front reinforcing elements 51, 52 are, on the one hand, fixed to the respective flanges 31, 32 by welding. For this purpose, the flanges 31, 32 and the front reinforcing elements 51, 52 define welding surfaces intended to be joined together.

(24) Moreover, the front reinforcing elements 51, 52 define additional welding surfaces 53, 54 (FIG. 2) for attachment by welding to the underframe component 3. As depicted in FIG. 2, the front reinforcing elements 51, 52 are thus welded on each side of the tunnel 2.

(25) The front reinforcing elements 51, 52 may thus make it possible to transmit to the tunnel 2 any load coming from the bearing zone, which means to say from the central part of the de Dion axle and from the flanges 31, 32, onto the walls of the tunnel 2. Because the tunnel 2 is a relatively strong element, this load can thus be absorbed with a limited risk of breakage.

(26) These front reinforcing elements 51, 52 thus allow reliability of the vehicle to be reconciled with lightness of weight.

(27) These front reinforcing elements 51, 52 may make it possible to absorb load derived from the engine in the event of a rear impact, but also in the event of a frontal impact, the engine then constituting a pressing mass. Stated differently, the front reinforcing elements 51, 52 make it possible to improve inertance of axis x.

(28) With reference to FIGS. 3 and 4, which will be discussed simultaneously, the motor vehicle rear structure further comprises a rear reinforcing element or rib 41.

(29) The rear reinforcing element 41 is fixed to the flanges 31, 32, for example by welding.

(30) The rear reinforcing element 41 has a relatively curved shape, one part 411 of the curve being welded to the flanges 31, 32, another part 412 of the element 41, opposite to the part 411, being welded to the underframe component 3.

(31) This rib 41 thus in some way constitutes a kind of natural end stop for the engine in the event of an impact, and makes it possible to improve the transmission of vibration loadings in z.

(32) These reinforcers 41, 51, 52 also provide this bearing zone with good endurance.

(33) The central bearing of the rear axle fixing is thus reinforced, this reinforcement making it possible to compensate for rotation loadings around the bearing about the axis y.

(34) As is evident from FIG. 4, the two assemblies formed by the respective front reinforcers, the corresponding flanges and the corresponding walls of the tunnel are each relatively aligned with the axis x of the vehicle thereby making it possible to ensure good transmission of load in x (arrow 62); and the assembly formed by the rear reinforcing element 41, the flanges and the ascending part of the underframe component, in contact with the rear reinforcing element, is relatively aligned with the axis z, thus allowing relatively good transmission of load in z, in the direction of the arrow referenced 61 in FIG. 3.

(35) The reinforcers 51, 52 and 41 allow load to be transmitted, in the direction of the respective arrows 61, 62 in FIGS. 3 and 4, while at the same time limiting the constraining of the bearing flanges so as to allow suitable rotation about the axis y and not use up all of the screw tightening torque to bring the flanges closer together, when the axle component is being mounted and the bearing is being tightened onto the flanges.

(36) The rear reinforcer 41 connects two zones that are relatively rigid and distant from one another with relatively low inertia on account of the proximity of the engine and the associated movements, and does so thanks to this relatively curved shape.

(37) The tunnel 2 is produced by roll forming, from a material that has a high elastic limit, so as to transmit load to the rest of the motor vehicle.