Device for protecting hybrid motor vehicles against impacts

Abstract

The present invention relates to a device for protecting the fuel tank (R) of a motor vehicle against rear impacts, said tank being mounted between two side members (L) extending under the body (C) of the vehicle, characterized in that it comprises a rigid frame (1) surrounding the tank (R) and being, on the one hand, connected at its front part to said side members and carrying, on the other hand, in its rear part, an anti-intrusion reinforcing element (2). Abstract figure: Fig. 1B

Description

Title of the invention: Device for protecting hybrid motor vehicles against impacts

[0001] The invention applies to the general field of so-called passive safety of hybrid motor vehicles.

[0002] More specifically, the invention relates to an improved device intended to improve the absorption of kinetic energy in the event of a high-speed impact against the rear of hybrid motor vehicles in order to protect various components and, in particular, their fuel tank.

[0003] Generally speaking, the passive safety of motor vehicles requires the presence of a kinetic energy absorption device which must satisfy a very strict regulatory protocol. This protocol proves even more difficult to satisfy for hybrid vehicles equipped, in the environment of their rear axle, with a bulky electric motor and a fuel tank and whose rear overhang is intended to be reduced compared to conventional vehicles in order to save overall mass, and therefore reduce the vehicle's fuel consumption.

[0004] Indeed, in the absence of sufficient protection, a high-speed impact on the rear leads to a rapid and very significant intrusion into the vehicle because, under the action of the thrust, the side member then tends to lift and, jointly, the rear axle and the electric motor move backward.

[0005] Furthermore, the kinetic energy resulting from this shock is such that the displaced components even impact the fuel tank, which generates risks of leakage and fire.

[0006] Patent EP435197A1 describes a rear body structure comprising, in particular, a pair of spacers connected to two side chassis parts so as to form a tank support chamber. However, this structure does not offer protection for the rear of the tank.

[0007] Furthermore, patent CN105936212B describes a structure intended for the peripheral protection of the tank against impacts. This structure is provided with springs ensuring the absorption by damping of the kinetic energy resulting from the impact.

[0008] Therefore, existing protective structures do not provide sufficiently reliable means to counter the thrust resulting from a high-speed impact.

[0009] However, in the event of a high-speed collision, the quantity of kinetic energy to be stored is very significant and it is therefore necessary for the protection device to have sufficient inertia and rigidity and thus avoid the intrusion and / or excessive deformation of components, in particular, of the fuel tank.

[0010] Furthermore, traditional devices for reinforcing the body of motor vehicles do not allow the fuel tank to be protected without requiring a reduction in its size, i.e. its volume, which penalizes the autonomy of the vehicle.

[0011] In this context, the invention aims to overcome the technical problems observed with previous solutions by proposing to integrate, in the device for protection against impacts occurring at the rear of the vehicle, an improved structure making it possible, on the one hand, to stabilize the side member and prevent it from lifting and, on the other hand, to stiffen the environment of the tank by integrating an anti-intrusion reinforcement element.

[0012] This object is achieved, according to the invention, by means of a device for protecting the fuel tank of a motor vehicle against rear impacts, said tank being mounted between two side members extending under the body of the vehicle, characterized in that it comprises a rigid frame surrounding the tank and being, on the one hand, connected at its front part to said side members and carrying, on the other hand, in its rear part, an anti-intrusion reinforcement element.

[0013] According to an advantageous characteristic, the frame is delimited laterally by two flanges ensuring the stabilization of the side members.

[0014] According to another characteristic, the frame is delimited in its front part by a cross member which is extended by two longitudinal arms ensuring the connection to the side members and allowing the transmission to the body of the vehicle of the thrust forces resulting from the impact.

[0015] Preferably, the arms are formed from two parallel angles of right-angle section.

[0016] According to yet another characteristic, the frame carries, around its perimeter, a set of tabs intended for fixing under the body of the vehicle.

[0017] Preferably, each side of the frame carries two fixing lugs.

[0018] According to a preferred embodiment, the anti-intrusion reinforcement element consists of an extruded profile with high inertia forming a stop and fixed transversely inside the frame.

[0019] According to a specific embodiment, this reinforcing element is formed from a profiled wall made of extruded aluminum.

[0020] According to another embodiment, the frame is made of stamped and welded steel sheets.

[0021] Another object of the invention is a motor vehicle equipped with an impact protection device having the characteristics defined above.

[0022] The device according to the invention for protection against impacts has optimal mechanical behavior with respect to impacts on the rear of the vehicle and at high speed which generate a very high level of kinetic energy.

[0023] This improved protection device complies with the regulatory and consumer specifications in the field of passive safety, in particular, that which relates to the sheet metal on the perimeter including the platform and the base of the vehicle, the area called "Unit AR", comprising, for vehicles with hybrid engines, the electric machine, the rear axle and the fuel tank while presenting a reduced size thanks to an optimization of the functions of the reinforced frame structure.

[0024] Thus, the protection device according to the invention, while preserving the volume of the tank, offers an additional technical solution applicable to any vehicle equipped with a secondary engine located at the rear, including vehicles equipped with an existing platform without requiring structural modification.

[0025] The framing element forms the equivalent of a "wall" which produces a very effective barrier or buffer effect to protect the tank. This element can be produced independently, then added in the factory during assembly of the vehicle and therefore without any impact on the fitting process.

[0026] Furthermore, the invention makes it possible to optimize the mass of the vehicle by producing the essential elements of the protection device in lightweight materials such as aluminum or steel / aluminum composite materials.

[0027] Finally, the protection device of the invention is very compact and reduces the overhang, which makes it easily compatible with current style lines.

[0028] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the attached and detailed drawings below.

[0029] [Fig. 1A] is a perspective view of a preferred embodiment of the protection device of the invention.

[0030] [Fig.lB] is a bottom view of the device of [Fig.lA].

[0031] [Fig.lC] is a side view of the device of [Fig.lA].

[0032] [Fig.2] is a detailed perspective view of the embodiment of the device of the figures IA to IC.

[0033] [Fig.3] is a partial sectional view along a longitudinal plane of the method of realization of the device of the invention of figures IA to IC.

[0034] [Fig.4] is a partial perspective and top view of the embodiment of the device of the invention of figures IA to IC in a rear impact situation according to the orientation of the arrows.

[0035] For clarity, identical or similar elements are identified by identical reference signs in the description and in the figures.

[0036] Naturally, the embodiments of the device of the invention illustrated by the figures presented above and described below are given only as non-limiting examples. It is explicitly provided that different embodiments can be proposed and combined with each other to propose others.

[0037] The invention relates to the field of passive safety and is more particularly concerned with protection against rear impacts of the fuel tank fitted to motor vehicles with secondary motorization of the thermal / electric hybrid type.

[0038] The protection device of the invention is capable and intended, at the same time, to counter the forward thrust resulting from a high-speed impact occurring at the rear of the vehicle in order to protect the tank and to avoid excessive deformations, in particular, in bending, of the chassis side members.

[0039] In hybrid vehicles and as illustrated by figures 1a, 1B and 1C, the electric machine E is generally mounted in the center of the cradle of the rear axle A and behind the fuel tank R which is, for its part, mounted between two side members L extending under the body C of the vehicle.

[0040] In the event of an impact at the rear of the vehicle and under the effect of the resulting thrust, the side members L tend to flex and lift while the electrical machine E moves back towards the tank R until, in the event of a high-speed impact, it hits it and damages it, which causes leaks and can even lead to a fire.

[0041] Thus, it appears that traditional hybrid vehicles suffer from a defect or insufficiency of means capable of effectively ensuring the absorption of kinetic energy in the event of a rear impact at high speed and of avoiding too great an intrusion.

[0042] The invention aims to solve this problem by integrating, in the rear part of the vehicle, a rigid frame 1 surrounding the tank R and being, on the one hand, connected at its front part to the boxes L and carrying, on the other hand, in its rear part, a reinforcing element 2 ensuring an anti-intrusion function.

[0043] As illustrated by figures 1A and 2, the frame 1 is delimited laterally by two flanges 11 ensuring the stabilization of the side members L. Thus, the high flexural inertia of the flanges 11 makes it possible to avoid or at least reduce their flexing in the event of an impact and to prevent their lifting. The bending of these flanges 11 towards the inside of the frame 1 further reinforces their resistance to deformation.

[0044] The frame 1 is delimited, in its front part, by a cross member 12 which is extended by two longitudinal arms 13 ensuring the connection to the side members L under the floor of the body C of the vehicle, as illustrated by figures 1B and 1C. The arms 13 ensure the transmission to the body C, and more particularly, to the hollow bodies of the floor, of the thrust forces resulting from the impact.

[0045] As illustrated by [Fig.2], the arms 13 are preferably formed of two parallel angles 13a, 13b of right-angled section. These angles are intended to cover and fit the section of stretchers secured to the floor.

[0046] The frame 1 carries, around its periphery, a set of lugs 14 intended for fixing under the body C of the vehicle. In the embodiment illustrated by [Fig.2], each side of the frame 1 carries two fixing lugs 14 which receive screws (not shown) which are fixed in tapped bores previously positioned on the body C. The profile of these lugs 14 is adapted to the profile of the zone of the body C with which they are intended to cooperate and which generally comprise bores existing as standard.

[0047] According to the invention, the anti-intrusion reinforcement element 2 consists of an extruded profile with high inertia and, preferably, non-deformable, attached and fixed transversely inside the frame 1 in a housing provided for this purpose, as illustrated in detail in [Fig. 3]. This housing is formed in a beam-shaped profile extending transversely to the rear of the frame 1.

[0048] The reinforcing element 2 forms, with the transverse beam of the frame 1, the equivalent of a “wall” providing a buffer or stop function. Thanks to the reinforcing element 2, any intrusion of the assembly consisting of the stack of electric machine E and rear axle A inside the frame 1 is blocked or at least limited in its travel towards the tank R, as illustrated by [Fig.4].

[0049] In a specific embodiment of the device of the invention, it is provided that the reinforcing element 2 is made from an extruded profile of a light but impact-resistant metal such as, for example, aluminum. Typically, the length of the aluminum element 2 is 175 mm, its height 75 mm and its thickness 2.5 mm.

[0050] the frame 1 is, for its part, made by welding various profiles made of stamped steel sheets. The steels used for the profiles constituting the frame 1 have different characteristics and thicknesses. The side plates 11 (DP780 steel) and the associated fixing lugs have a thickness of between 2.0 mm and 2.5 mm, the cross member 12 (FB60 steel) has a thickness of 2.3 mm, the arm angles 13 (FB60 steel) have a thickness of 2.4 mm, the front fixing lugs (XES steel) have a thickness of 3 mm and the rear fixing lugs (HD380 steel) have a thickness of 2 mm.

Claims

Claims

1. Device for protecting the fuel tank (R) of a motor vehicle against rear impacts, said tank being mounted between two side members (L) extending under the body (C) of the vehicle, said device comprises a rigid frame (1) surrounding the tank (R) and carrying, on the one hand, in its rear part, an anti-intrusion reinforcing element (2) and being, on the other hand, connected at its front part to said side members (L) by a cross member (12) which is extended by two longitudinal arms (13) ensuring the connection to the side members and allowing the transmission to the body (C) of the vehicle of the thrust forces resulting from the impact, characterized in that said arms (13) are formed of two parallel angles (13a, 13b) of right-angled section.

2. Device according to claim 1, characterized in that said frame (1) is delimited laterally by two flanges (11) ensuring the stabilization of the side members (L).

3. Device according to one of the preceding claims, characterized in that said frame (1) carries, on its periphery, a set of tabs (14) intended for fixing under the body (C) of the vehicle.

4. Device according to the preceding claim, characterized in that each side of the frame (1) carries two fixing lugs (14).

5. Device according to one of the preceding claims, characterized in that said anti-intrusion reinforcement element (2) consists of an extruded profile with high inertia forming a stop and fixed transversely inside the frame (1).

6. Device according to the preceding claim, characterized in that said reinforcing element (2) is formed from a profiled wall made of extruded aluminum.

7. Device according to one of the preceding claims, characterized in that the frame (1) is made of stamped and welded steel sheets.

8. Motor vehicle equipped with an impact protection device according to one of the preceding claims.

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