Underbody for a motor vehicle and motor vehicle comprising such an underbody

Abstract

The invention relates to an underbody (6) for a motor vehicle, which comprises an upper floor (8), a central frame (10) comprising a front crossmember (22), a rear crossmember (24) and two side sills (26), the upper floor (8) being attached to the central frame (10), the underbody (6) comprising a lower closure plate attached to a lower perimeter of the frame (10), the upper floor (8) and the lower closure plate defining, inside the frame (10), an energy storage space intended to accommodate at least one energy storage module constituting a traction battery of the vehicle.

Description

[0001] TITLE: Underbody for motor vehicle and motor vehicle comprising such an underbody

[0002] Technical field

[0003] The technical field of the invention is motor vehicles, in particular the underbodies of electric motor vehicles.

[0004] In particular, the present invention relates to a base for a motor vehicle and a motor vehicle comprising such a base.

[0005] Previous techniques

[0006] An electric motor vehicle known from the prior art comprises energy modules, an aluminum casing forming a sealed enclosure in which the energy modules are installed and a base provided with a floor under which the entire casing and energy modules are fixed.

[0007] The housing includes a top plate and a reinforced bottom plate opposite the top plate, the housing being secured to the floor so that the top plate faces the floor.

[0008] The energy modules are arranged in the housing so that they rest on the reinforced bottom plate. For example, the entire housing and energy modules typically weigh more than 400 kilograms.

[0009] The reinforced bottom plate is subjected to heavy loads during vehicle use, particularly in terms of vibrations and endurance.

[0010] In addition, the housing is a high mass element of the vehicle.

[0011] Statement of the invention

[0012] The present invention therefore aims to overcome all or part of the aforementioned drawbacks, and to propose a base for a motor vehicle of reduced mass, to guarantee high stiffness of the vehicle and to provide a feeling of safety to the passengers of the vehicle.

[0013] The present invention relates to a base for a motor vehicle, the base comprising an upper floor, a central frame comprising a front cross member, a rear cross member and two side skirts, the upper floor being fixed to the central frame, the base comprising a lower closing plate fixed to a lower periphery of the frame, the upper floor and the lower closing plate delimiting inside the frame an energy storage space intended to accommodate at least one energy storage module constituting a traction battery of the vehicle.

[0014] The storage space delimited by the upper floor fixed to the central frame and by the lower closing plate fixed on the lower periphery of the frame forms an integral part of the base. Such a base does not include a housing provided with an upper plate as present on the vehicles known from the prior art.

[0015] Advantageously, the base comprises at least one fixing member housed in the storage space, arranged on the upper floor and configured to suspend the modules.

[0016] Optionally, the thickness of the lower closing plate is less than 2 millimeters.

[0017] Advantageously, the closing plate is fixed only to the lower perimeter of the central frame.

[0018] In one embodiment, at least one of the two flaps is formed by stamping and / or profiling a plate with a thickness of between 1 and 1.5 millimeters.

[0019] The front cross member can be formed by stamping and / or profiling a plate with a thickness of between 1 and 1.8 millimeters.

[0020] The rear cross member can be formed by stamping and / or profiling a plate with a thickness of between 1 and 1.8 millimeters.

[0021] The upper floor can be formed by stamping and / or profiling a plate with a thickness between 0.6 and 1 millimeter.

[0022] Advantageously, the lower closing plate is fixed to the lower periphery of the frame so that a periphery of the upper floor is clamped between the frame and the lower closing plate.

[0023] In one embodiment, at least one of the two flaps comprises a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as steel.

[0024] The front crossmember may comprise a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as a steel.

[0025] The rear crossmember may comprise a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as a steel.

[0026] The present invention also relates to a motor vehicle comprising a base as defined above.

[0027] Advantageously, the vehicle comprises at least one energy storage module fixed to the upper floor, a gap remaining between the module and the lower closing plate. Optionally, the vehicle comprises a right rear axle ball joint and a left rear axle ball joint, the rear cross member extending between the right and left rear axle ball joints.

[0028] Brief description of the drawings

[0029] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0030] [Fig 1] schematically illustrates a motor vehicle according to the invention;

[0031] [Fig 2] schematically illustrates a top view of a central part of a base according to the invention;

[0032] [Fig 3] schematically illustrates a cross-section of the base of Figure 2; and

[0033] [Fig 4] schematically illustrates a bottom view of the base of Figure 2.

[0034] Detailed description

[0035] Figure 1 schematically represents a motor vehicle 2, typically an electric motor vehicle comprising a battery integrating a plurality of modules 4, for example in the form of parallelepiped and / or flexible and / or prismatic and / or cylindrical energy cells.

[0036] In the remainder of the description, the terms "longitudinal", "transverse", "vertical", "front", "rear", "left", "right", "upper", "lower", "under" and "on" are understood in relation to the usual orthogonal reference frame for motor vehicles, shown in Figure 1, and including:

[0037] - a longitudinal axis X, horizontal and directed from the front to the rear of the vehicle 2;

[0038] - a transverse axis Y, horizontal, perpendicular to the X axis and directed from the left to the right of the vehicle 2 moving forward;

[0039] - a Z axis, orthogonal to the X and Y axes, vertical and directed from bottom to top.

[0040] The vehicle 2 comprises a base 6 provided with an upper floor 8, a central frame 10 and a lower closing plate 12. The base 6 also comprises front side members 14 and rear side members 16.

[0041] The upper floor 8 faces the roof 18 of the vehicle 2 and forms a surface delimiting the passenger compartment 20 of the vehicle 2.

[0042] Figure 2 schematically illustrates a top view of the central part of the base 6. The central frame 10 comprises a front cross member 22 on which the front side members 14 are fixed and a rear cross member 24 on which the rear side members 16 are fixed.

[0043] The central frame 10 comprises two lateral sills 26 connected to the front and rear crossmembers 22, 24 of the central frame 10. Each sill 26 forms a lateral part of the vehicle 2, in particular a lateral part located longitudinally between the wheels of the vehicle 2 and vertically under the doors of the vehicle 2. The sills 26 are also called rocker panels or lower flaps.

[0044] The vehicle 2 comprises a plurality of central crosspieces 28 fixed to the upper floor 8. The central crosspieces 28 are, for example, welded to the upper floor 8, the absence of a fixing hole in the upper floor 8 making it possible to guarantee the sealing, in particular sound and / or thermal, of the passenger compartment 20 at the level of the upper floor 8.

[0045] The central crosspieces 28 are each in contact on either side in the transverse direction of the vehicle 2 with a flap 26. Each central crosspiece 28 allows the attachment of elements of the passenger compartment 20, in particular seats of the vehicle 2 and / or belts of the vehicle 2 and / or elements for attaching luggage and / or a child seat. Advantageously, each central crosspiece 28 contributes to the stiffness of the vehicle 2 and to the resistance of the vehicle 2 in the event of a side impact.

[0046] The lower plate 12 is fixed to a lower periphery 30 of the central frame 10, the lower periphery 30 being formed in particular of a lower surface of the front cross member 22 of the central frame 10, of a lower surface of the rear cross member 24 of the central frame 10 and of a lower surface of the two lateral flaps 26.

[0047] Advantageously, the lower periphery 30 of the central frame 10 is flat or substantially flat.

[0048] By “substantially flat” is meant that the different surfaces making up the lower periphery 30 of the central frame 10 installed on the vehicle 2 are spaced along the vertical axis Z of the vehicle 2 by less than one centimeter.

[0049] The lower plate 12 is, for example, screwed to the lower periphery 30 of the central frame 10.

[0050] The upper floor 8 is fixed to the central frame 10. For example, the upper floor 8 extends longitudinally between the front cross member 22 of the central frame 10 and the rear cross member 24 of the central frame 10, as well as vertically from the central cross members 28 of the vehicle 2 to the lower periphery 30 of the central frame 10 so that a periphery of the upper floor 8 is fixed to the lower periphery 30 of the central frame 10. Advantageously, the lower plate 12 is fixed, in particular screwed, to the lower periphery 30 of the central frame 10 so that the periphery of the upper floor 8 is vertically clamped between the central frame 10 and the lower plate 12.

[0051] The upper floor 8 and the lower plate 12 jointly delimit inside the central frame 10 a storage space 32 accommodating the batteries 4 of the vehicle 2, represented below in figure 4.

[0052] Figure 3 schematically illustrates a cross-section of the base 6.

[0053] The base 6 comprises a plurality of fixing members 34 housed in the storage space 32. Each fixing member 34 is fixed to the upper floor 8, in particular welded to the upper floor 8.

[0054] Each fastening member 34 is configured to suspend at least one battery 4 from the vehicle 2. By "suspending at least one battery from the vehicle" is meant that the battery 4 is supported by the fastening member 34 so that the battery 4 is suspended from the fastening member 34.

[0055] For example, each fixing member 34 comprises a beam extending in the storage space 32, in particular longitudinally. The beam comprises at least one hole formed in a section of the beam, the battery 4 comprising at least one fixing lug cooperating with the hole to suspend the battery 4 from the beam.

[0056] Advantageously, a vertical clearance 36 remains between each battery 4 housed in the storage space 32 and the upper floor 8 in order to electrically isolate the battery 4 from the upper floor 8.

[0057] Preferably, each fixing member 34 comprises an electrically insulating material in order to electrically insulate the batteries 4 from the upper floor 8.

[0058] Optionally, the base 6 comprises an insulating foam (not shown), in particular for thermal protection, surrounding the battery 4 in the storage space 32.

[0059] Preferably, the thickness of the lower closing plate 12 is less than two millimeters. Since the lower plate 12 does not support the weight of the batteries 4, the thickness of the lower plate 12 is reduced, in particular in order to reduce the mass of the underbody 6 of the vehicle 2.

[0060] The lower plate 12 provides protection for the battery 4, particularly against road debris. Advantageously, a vertical gap 38 remains between each battery 4 fixed to the upper floor 8 by means of a fixing member 34 and the lower plate 12. The lower plate 12 comprises, for example, aluminum and / or a fiber-reinforced plastic material.

[0061] Figure 4 schematically illustrates a bottom view of the lower plate 12.

[0062] Optionally, the lower plate 12 includes an inspection hatch 40 allowing access to the storage space 32 without dismantling the lower plate 12.

[0063] The lower plate 12 comprises reinforcing elements 42, for example spacers, extending vertically between the lower plate 12 and the fixing members 34 in order to increase the vertical stiffness of the base 6.

[0064] Alternatively, the base 6 does not include the reinforcing elements 42, the lower closing plate 12 being only fixed to the lower periphery 30 of the central frame 10 of the base 6.

[0065] The vehicle 2 comprises a right rear axle ball joint and a left rear axle ball joint (not shown). The underbody 6 comprises a first fixing part 44 for the right rear axle ball joint and a second fixing part 46 for the left rear axle ball joint.

[0066] The rear cross member 24 of the central frame 10 is intended to extend between the right rear axle ball joint and the left rear axle ball joint, the rear cross member 24 of the central frame 10 extending between the first fixing part 44 of the right rear axle ball joint and the second fixing part 46 of the left rear axle ball joint. Thus, the volume of the storage space 32 is maximized.

[0067] The stiffness of the vehicle 2, also called torsional body stiffness, is notably measured by applying a torque around the central longitudinal axis of the vehicle 2, by measuring an angle formed by a transverse axis extending between rear shock absorber mountings (not shown) of the vehicle 2 and by calculating the value of the ratio between the applied torque and the angle formed by the transverse axis extending between rear shock absorber mountings relative to the transverse axis of the orthogonal reference frame.

[0068] Increasing the stiffness of vehicle 2 helps reduce unwanted noise during operation of vehicle 2 and increases the comfort and confidence of passengers in vehicle 2.

[0069] Optionally, the two side flaps 26 are formed by stamping and / or profiling a plate with a thickness of between 1 and 1.5 millimeters.

[0070] Optionally, the front and rear cross members 22, 24 of the central frame 10 are formed by stamping and / or profiling a plate with a thickness of between 1 and 1.8 millimeters. Optionally, the upper floor 8 is formed by stamping and / or profiling a plate with a thickness of between 0.6 and 1 millimeter.

[0071] In one embodiment, the upper floor 8 is welded to the two side skirts 26. These architectural choices allow the creation of a base 6 of high stiffness and reduced mass compared to a vehicle known from the prior art.

[0072] The vehicle 2 comprising the base 6 provided with the central frame 10, the upper floor 8 and the lower plate 12 has, for example, a stiffness of more than 33 kilo Newton meters per degree.

[0073] Advantageously, the two lateral sills 26, the front cross member 22 of the central frame 10 and the rear cross member 24 of the central frame 10 each comprise a material having an elastic limit of a value greater than or equal to 400 megapascals. For example, a value greater than or equal to 1000 megapascals, such as steel. Thus, the base 6 is particularly stiff and offers a feeling of comfort to the passengers of the vehicle 2.

Claims

CLAIMS 1. Base (6) for a motor vehicle (2), the base (6) comprising an upper floor (8), a central frame (10) comprising a front cross member (22), a rear cross member (24) and two side flaps (26), characterized in that the upper floor (8) is fixed to the central frame (10), the base (6) comprising a lower closing plate (12) fixed to a lower periphery (30) of the frame (10), the upper floor (8) and the lower closing plate (12) delimiting inside the frame (10) an energy storage space (32) intended to accommodate at least one energy storage module (4) constituting a traction battery of the vehicle (2).

2. Base (6) according to claim 1, comprising at least one fixing member (34) housed in the storage space (32), arranged on the upper floor (8) and configured to suspend the modules (4) of the vehicle (2).

3. Base (6) according to one of claims 1 and 2, in which the thickness of the lower closing plate (12) is less than 2 millimeters.

4. Base (6) according to any one of claims 1 to 3, in which at least one of the two flaps (26) is formed by stamping and / or profiling a plate with a thickness of between 1 and 1.5 millimeters.

5. Base (6) according to any one of claims 1 to 4, in which the front cross member (22) is formed by stamping and / or profiling a plate with a thickness of between 1 and 1.8 millimeters and / or in which the rear cross member (24) is formed by stamping and / or profiling a plate with a thickness of between 1 and 1.8 millimeters.

6. Base (6) according to any one of claims 1 to 5, in which the upper floor (8) is formed by stamping and / or profiling a plate with a thickness of between 0.6 and 1 millimeter.

7. Base (6) according to any one of claims 1 to 6, in which the lower closing plate (12) is fixed to the lower periphery (30) of the frame (10) so that a periphery of the upper floor (8) is clamped between the frame (10) and the lower closing plate (12).

8. Base (6) according to any one of claims 1 to 7, in which at least one of the two flaps (26) comprises a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as steel, and / or in which the front cross member (22) comprises a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as a steel, and / or wherein the rear crossmember (24) comprises a material having an elastic limit of a value greater than or equal to 400 megapascals, preferably greater than or equal to 1000 megapascals, such as a steel.

9. Motor vehicle (2) comprising a base (6) according to any one of claims 1 to 8, and at least one energy storage module (4) fixed to the upper floor (8), a gap (38) remaining between the module (4) and the lower closing plate (12).

10. Motor vehicle (2) according to claim 9, comprising a right rear axle ball joint and a left rear axle ball joint, the rear cross member (24) extending between the right and left rear axle ball joints.

Images