FR3119130A1 - Vehicle with an underbody structure comprising an impact protection device - Google Patents

Abstract

Vehicle with an underbody structure (10) comprising at least one body part, the vehicle comprising at least one element (14, 16) fixed under the body part, and a protection device (18) against shocks to protect the or at least one of the elements fixed under the body part. At least one element and the impact protection device (18) are fixed to the body part by at least one common fixing device (20). The common fixing device includes independent fixing means so that the impact protection device can be mounted or dismounted independently of the element. Figure to be published with abstract: Fig. 2

Description

Vehicle with an underbody structure comprising an impact protection device

The present invention relates to the field of motor vehicles comprising, in the underbody structure, a device for protecting against shocks an element mounted under the body of the vehicle.

Motor vehicles, and in particular electric motor vehicles, are equipped with a propulsion battery making it possible to drive an electric motor. The propulsion battery is substantially parallelepipedic in shape and is generally arranged in a battery box fixed in the underbody structure, under the body of the vehicle at the level of the front and rear seats. Commonly, the battery box is mounted suspended under the body of the vehicle constituting a prominent fairing element according to the vertical.

The fixing of the battery tray under the body must be made sufficiently robust to limit the risk of falling while driving the vehicle, but also removable to allow maintenance operations. For safety and insurance reasons, it is also desirable that the dismantling of the battery box be reserved for a specialized technician.

The location of the battery in the base structure allows easy access in the event of maintenance, but exposes the battery to the risk of shocks, in particular by obstacles from the road.

These risks of impact exist during reversing maneuvers such as on a sidewalk, and can also be significant when the vehicle is moving on the road because objects placed on the road can arrive at high speed under the vehicle. It is therefore desirable to be able to install a shock protection device for the battery or for another sensitive element mounted under the body of the vehicle such as in the underbody structure.

The installation of a protection device for an element, such as a propulsion battery, mounted under the body of the vehicle, such as for example a device of the deflector type or a device comprising a protective plate poses various problems. Indeed, to limit the transmission of forces due to an impact, it is desired to fix such a device to the body of the vehicle and not to an element mounted under the body. An impact protection device must also be easily replaceable, without special tools or skills, in the event of damage after an impact. Finally, the layouts of the underbody structures of current vehicles are made to maximize the dimensions of the propulsion battery and leave little space to attach a protection device for the battery box to the vehicle body.

There is therefore a need for a means of protecting an element mounted under the body which is easily mountable and removable and which can be fixed to the body of the vehicle despite the significant space constraints.

Devices for protecting against shocks of a motor vehicle element mounted under the body are known, such as, for example, in the document EP3007936. This document discloses a protection device formed by an underbody element made of fiber-reinforced plastic material. The underbody element is a shell which forms a fairing and allows the passage of a steering shaft. The goal is to provide protection with a lightweight device. This document does not deal with the assembly of a device with strong constraints at the level of the fixing on the body, nor the assembly and disassembly of the device.

DE 10204116836 discloses a shock protection device for a propulsion battery mounted under the body of a vehicle. The protection device comprises a deflector mounted in front of the propulsion battery in the direction of travel of the vehicle. The deflector can be lowered or raised depending on the speed of the vehicle so as not to immobilize the vehicle in the event of an impact. This document does not deal either with the problems of fixing or mounting/dismounting the deflector.

In document FR 2 950 852, a device for protecting a vehicle element mounted under the body comprises a fairing element mounted protruding under the body so as to form a low point which is vertically lower than an element of the vehicle. The device is arranged at the rear of the vehicle so as to protect the element during reversing manoeuvres. The fairing element comprises a support surface with a slope making it possible to lift the vehicle by contact with an obstacle and thus avoid an impact against the element.

None of the known documents of the state of the art offers a solution against the shocks of an element mounted under the body that takes into account the space and assembly constraints mentioned above.

The object of the present invention is to respond to at least one of the problems and/or drawbacks of the state of the art. In particular, the aim of the invention is to propose a motor vehicle comprising a device for protecting an element mounted under the body of the vehicle which responds both to space constraints and which is easily mountable and removable.

To this end and according to a first aspect, the invention relates to a vehicle with an underbody structure comprising at least one body part, the vehicle comprising at least one element fixed under the body part, and a device for protection against shocks to protect the or at least one of the elements fixed under the body part; the vehicle is remarkable in that at least one element and the impact protection device are fixed to the body part by at least one common fixing device, this common fixing device comprising independent fixing means so as to that the impact protection device can be mounted or dismounted independently of the element.

The impact protection device can be fixed using the same fixing points as those provided for the fixing of an underbody mounted element in the underbody structure of the vehicle. These attachment points can be those of the element it protects or those of another element. Attaching the impact protection device therefore does not require the installation of new attachment points on the body part and meets the space constraints mentioned above. In addition, the attachment of the shock protection device is independent of the attachment of the element. Thus, it is possible to dismantle only the securing device against shocks, without causing the dismantling of another element, facilitating maintenance operations.

In embodiments of the invention, the fixing means of the common fixing device comprise two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the attachment of the protection device against shocks independently of the attachment of the element. These common fastening means are simple to manufacture and use.

Preferably, the fixing means of the common fixing device comprise a head and two coaxial threaded rods extending on either side of the head; a first threaded rod being intended for the fixing by clamping of an element to the body part of the vehicle, and a second threaded rod being intended for the fixing by clamping of the protection device against shocks to the body part of the vehicle. Preferably, the head includes gripping means.

Advantageously, the two coaxial threaded rods have different diameters, in order to be able to adapt to the holes forming the attachment points of the element and of the device for protection against shocks.

To facilitate the introduction of a threaded rod into an orifice or attachment point of the body part, of an element, or of the device for protection against shocks, the threaded rod may comprise a free end with a guide part such as for example a conical or cylindrical part of reduced diameter.

In some embodiments, the fixing means of the common fixing device comprise a first screw intended for the fixing by clamping of an element to the body part of the vehicle, the first screw comprising a head with a tapped hole allowing the insertion of a second screw intended for fixing by tightening the device for protection against shocks to the body part of the vehicle; preferably, the tapped hole extends from the head of the first screw and through the shank of the first screw.

Preferably, the tightening torque applied for fixing the element is at least 20 N.m greater than the tightening torque applied for fixing the protection device against shocks; preferably higher by at least 30 N.m. The large difference between the two tightening torques makes it possible to loosen the impact protection device without having to hold the common fixing device which remains immobile by the fixing between the element and the vehicle body. Advantageously, the tightening torque applied for fixing the element is at least 80 N.m; preferably at least 90 N.m; preferably at least 100N.m; and the tightening torque applied for securing the impact protection device is at least 60 N.m; preferably at least 70 N.m; preferably at least 80 N.m.

In embodiments, the elements comprising a battery box, the vehicle is remarkable in that the protection device against shocks is fixed below the body part by a common fixing device with the battery box.

Advantageously, the elements further comprising a front cradle arranged forward relative to the battery box, a space between the battery box and the front cradle; the vehicle is remarkable in that the impact protection device is fixed vertically below the space between the battery box and the front subframe, and in that the impact protection device is fixed by a device fixing device common with the battery box and by a fixing device common with the front subframe.

Preferably, the impact protection device extends vertically downwards lower than the element intended to be protected; preferably at least 1 cm lower; preferably at least 1.5 cm lower. This distance allows the impact protection device to encounter an obstacle placed on the road before the element and thus to protect the latter well.

According to a second aspect, the invention relates to a common fastening device comprising fastening means by clamping for at least two elements intended to be mounted under the body in the underbody structure of a motor vehicle according to the first aspect, the means for fastener comprising two coaxial threaded rods, and at least one head; each threaded rod allowing the tightening of a respective element independently of the other.

According to a third aspect, the invention relates to the use of a common fixing device according to the second aspect in a motor vehicle for fixing at least two underbody elements in the underbody structure of said motor vehicle.

According to a fourth aspect, the invention relates to a method for securing a device for protection against impacts, and an element under a body part of a vehicle underbody structure, by at least one securing device. common fixing comprising independent fixing means; the fastening means comprising two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the attachment of the protection device against shocks independently of the attachment of the element; the method comprising the steps of: fixing the element to the body part by clamping via a first threaded rod of the fixing means of the common fixing device; fix the protection device against shocks to the body part by clamping via a second threaded rod of the fixing means of the common fixing device.

Other particularities and characteristics of the invention will emerge from the detailed description of at least one advantageous embodiment presented below, by way of illustration, with reference to the appended drawings. These show:

there is a partial bottom view of a vehicle without an impact protection device;

there is a partial bottom view of a vehicle according to one embodiment of the invention;

there is a partial side sectional view of the vehicle from the , showing an impact protection device;

there shows a side sectional view of a detail of a fixing means of a common fixing device in one embodiment of a vehicle according to the invention;

there shows a side sectional view of an attachment means of a common attachment device in the embodiment of the ;

there shows a side sectional view of a common fastener in the embodiment of the ;

there shows a side sectional view of a detail of a fixing means of a common fixing device in another embodiment of a vehicle according to the invention;

there shows a side sectional view of an attachment means of a common attachment device in the embodiment of the ;

there shows a side sectional view of a common fastener in the embodiment of the .

In the rest of the description, the term “understand” is synonymous with “include” and is not limiting in that it authorizes the presence of other elements in the vehicle to which it refers. It is understood that the term “include” includes the terms “consist of”.

Similarly, the terms "lower", "upper", "high" and "low" will be understood according to their usual definition, in which the terms "lower" and "low" indicate a greater proximity to the ground according to the direction vertical than the terms "upper" and "high" respectively.

The terms "longitudinal", "transverse", "front" and "rear" shall be understood in relation to the general orientation of the vehicle as taken in its normal direction of travel.

In the rest of the description, elements having an identical structure and/or similar functions will be designated by the same reference.

There shows a partial bottom view of a vehicle, of the motor vehicle type, comprising a base structure 10. In the , the front of the vehicle is at the top of the figure. The vehicle is represented here without a protection device against shocks so as to show a body part 12 and the space available at the level of the body part.

The body part 12 or sill has a surface which in use of the vehicle is facing the road. The body part 12 can serve as a support for fixing at least one element under said body part. By way of non-limiting examples, the elements fixed at the level of the base structure can comprise a tank, a battery box in which one or more battery modules are located, sensitive equipment such as pipes, electrical harnesses, connectors, sensors, and also a front subframe.

In the embodiment of Figures 1 and 2, a battery box 14 and a front subframe 16 are both fixed below the body part 12. These elements are arranged facing the rolling surface of the vehicle, and are liable to be directly exposed to shocks due to projections such as gravel or stones, or to obstacles present on the rolling surface.

The attachment of an element to the body part must be robust so as to limit the risk of an element falling on the road while the vehicle is in motion. In the example of a screw fixing, the tightening is ensured with a predetermined torque so as to form a so-called safe tightening.

As shown at , the base structure further comprises a protection device 18 against shocks to protect at least one of the elements against shocks from objects passing below the vehicle.

The arrangement of the protection device 18 against shocks is preferably between an edge of the vehicle and the element intended to be protected against shocks. Typically in the case of protection in forward motion of the vehicle, the protection device 18 is arranged in front of the vehicle with respect to the element intended to be protected.

At least one element and the protection device 18 against shocks are fixed to the body part 12 by at least one common fixing device 20. This common fixing device comprises two independent fixing means so that the protection can be mounted or dismounted independently of the element.

The fixing means of the common fixing device 20 can be fixing means by clamping such as for example by screw-nut systems, but it is also possible to use other fixing means, such as for example fixing means removable by embedding with a locking system or other.

The fixing means of the common fixing device can be fixing means by clamping comprising two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the tightening of an element independently of the tightening of the protection device against shocks. The threaded rods are then introduced into holes provided in the body part, corresponding with holes in the element, and in the protection device against shocks. Tightening can be done by means of a nut or a tapped hole.

The impact protection device 18 can be fixed by one or a plurality of common fixing devices, and can be fixed by common fixing devices with one or more elements. A plurality of fastening devices will be preferred so as to ensure good hold of the fastening element. The number and position of the common fixing devices depend essentially on the dimensions of the protection device against shocks and of the element intended to be protected by this protection device. For example, the protection device can be fixed at 2 points, 4 points, 6 points by as many fixing devices.

In the arrangement shown in , the protection device 18 against shocks is arranged so as to protect the battery box 14 against shocks. The shock protection device is, in this embodiment, fixed to the body part 12 at 6 fixing points, comprising 4 common fixing points with the battery box 14, and 2 common fixing points with the front subframe 16.

In the arrangement shown in , a space 22 between the battery tray 14 and the front cradle 16 allows the passage of motor power cables. The protection device 18 against shocks is fixed vertically below the space 22 between the battery box and the front subframe, so as to partially obstruct this space 22.

The protection device 18 against shocks can have a predetermined shape and dimensions, adapted to the element intended to be protected. The shock protection device can form a “breakwater” type device configured to encounter an obstacle before the device intended to be protected. The shock protection device can also entirely or partially cover an element intended to be protected.

The protection device is preferably a projecting element mounted under the body of the vehicle. As shown at , the protective device then extends vertically downwards lower than the element intended to be protected; preferably at least 1 cm lower; preferably at least 1.5 cm lower. In other words, the low point of the protective device, ie the point which is vertically closest to the ground when the vehicle is placed on flat ground, is lower than the low point of the element intended to be protected. .

In the embodiment of Figures 2 and 3, the protection device is a rectilinear profile which has a section in Ω. The tabs of the protective device allow it to be attached to the body part.

Embodiments of the common fixing means 20 will now be described with reference to FIGS. 4 to 9.

According to one embodiment of the invention shown in Figures 4, 5 and 6, the common fixing device 20 comprises fixing means. The fastening means comprise a head 24 and two coaxial threaded rods extending on either side of the head; a first threaded rod 26 being intended for the fixing by clamping of an element to the body part of the vehicle, and a second threaded rod 28 being intended for the fixing by clamping of the protective device 18 against shocks to the body part of the vehicle.

In this embodiment, a first nut 30 is engaged around the first threaded rod 26 to ensure the tightening of the element as shown in , and a second nut 32 is engaged around the second threaded rod 26 to ensure the tightening of the protection device against shocks, as shown in .

The head 24 may comprise gripping means such as for example a hexagonal or square head shape or else a cross indentation.

The two coaxial rods 26, 28 may have identical or different diameters to ensure appropriate holding of the element or protection device. In this embodiment, the first threaded rod 26 has a larger diameter than the second threaded rod 28, but the reverse is also possible.

To facilitate the introduction of a threaded rod, the latter may comprise one end with a guide part such as for example a conical or cylindrical part of reduced diameter.

According to another embodiment of the invention shown in FIGS. 7, 8 and 9, the common fixing device 34 comprises fixing means which comprise a first screw 36 intended for the fixing by clamping of an element to the part of body of the vehicle, and a second screw 38 intended for fixing by clamping the protection device against shocks to the body part of the vehicle.

The first screw 36 comprises a head 40 with a tapped hole 42 allowing the insertion of the second screw 38 for clamping the protection device against shocks to the body part of the vehicle.

In this embodiment, a nut 44 is engaged with the first screw 36 to ensure the tightening of the element as shown in , while the tightening of the protection device against shocks is carried out by engagement of the second screw 38 in the tapped hole of the first screw 36 as shown in .

In variants of this embodiment, the tightening of the element is done using the second screw, and the tightening of the protection device against shocks is done using the first screw.

In the embodiments comprising a common fixing device with clamping fixing means, the tightening torque applied for tightening the element is greater by at least 20 N.m than the tightening torque applied for tightening the protection 18 against shocks. This allows the clamping and release of the impact protection device to be carried out without requiring a holding action of the common fixing device which remains fixed by the clamping of the element.

The invention also relates to a method for fixing a protective device against impacts, and an element under a body part of an underbody structure of a vehicle by at least one common fixing device. The common fixing device comprises independent fixing means. The fastening means comprise two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the tightening of the protection device against shocks independently of the tightening of the element.

The method comprises a step of: fixing the element to the body part by tightening via a first threaded rod of the common fixing means; and a step of: fixing the protection device against shocks to the body part by tightening via a second threaded rod of the common fixing means. The order of the steps can be changed.

Claims (10)

Vehicle with an underbody structure (10) comprising at least one body part (12), the vehicle comprising at least one element (14, 16) fixed under the body part, and a protection device (18) against impacts to protect the or at least one of the elements fixed under the body part; the vehicle is characterized in that at least one element and the device (18) for protection against shocks are fixed to the body part (12) by at least one common fixing device (20, 34), this device common attachment comprising independent attachment means so that the impact protection device can be mounted or dismounted independently of the element. Vehicle according to Claim 1, characterized in that the fixing means of the common fixing device (20, 34) comprise two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the attachment of the protection device against shocks independently of the attachment of the element. Vehicle according to any one of the preceding claims 1 or 2, characterized in that the fixing means of the common fixing device (20) comprise a head (24) and two coaxial threaded rods extending on either side of the head ; a first threaded rod (26) being intended for the fixing by clamping of an element to the body part of the vehicle, and a second threaded rod (28) being intended for the fixing by clamping of the protection device (18) against shocks to the body part of the vehicle (12); preferably, the head (24) includes gripping means. Vehicle according to any one of Claims 2 or 3, characterized in that the two coaxial threaded rods (26, 28) have different diameters. Vehicle according to any one of the preceding claims 1 or 2, characterized in that the fixing means of the common fixing device (34) comprise a first screw (36) intended for the fixing by clamping of an element to the part of body of the vehicle, the first screw comprising a head (40) with a threaded hole (42) allowing the insertion of a second screw (38) intended for the fixing by clamping of the protection device against shocks to the body part of the vehicle ; preferably, the tapped hole extends from the head of the first screw and through the shank of the first screw. Vehicle according to any one of the preceding claims 2 to 5, characterized in that the tightening torque applied for fixing the element is greater by at least 20 N.m than the tightening torque applied for fixing the protective device ( 18) against shocks. Vehicle according to any one of the preceding claims 1 to 6, the elements comprising a battery box (14), the vehicle is characterized in that the protective device (18) against shocks is fixed below the body part (12) by a common fixing device with the battery tray. Vehicle according to claim 7, the elements further comprising a front cradle (16) disposed forward of the battery box (14), a space (22) between the battery box and the front cradle; the vehicle is characterized in that the protection device (18) against shocks is fixed vertically below the space (22) between the battery box and the front subframe, and in that the protection device (18 ) against shocks is fixed by a common fixing device with the battery tray (14) and by a common fixing device with the front subframe (16). Vehicle according to any one of the preceding claims 1 to 8, characterized in that the protective device (18) against shocks extends vertically downwards lower than the element intended to be protected; preferably at least 1 cm lower. Method for fixing a protective device (18) against shocks, and an element under a body part (12) of an underbody structure (10) of a vehicle, by at least one fixing device common comprising independent fastening means; the fastening means comprising two coaxial threaded rods, and at least one head; the threaded rods respectively allowing the attachment of the protection device against shocks independently of the attachment of the element; the method comprising the steps of:fixing the element to the body part by clamping via a first threaded rod of the fixing means of the common fixing device;fixing the impact protection device to the body part by clamping via a second threaded rod of the fixing means of the common fixing device.