FR3148749A1 - VEHICLE SEAT SUSPENSION DEVICE - Google Patents

Abstract

The invention relates to a vehicle seat (1) comprising a support frame (2) for the seat (3) and the backrest (4) of a seat (1) and a member for fixing said seat (1) to a vehicle, at least one suspension device being positioned between said support frame (2) and said fixing member, characterized in that the suspension device comprises at least one deformable sphere (22) with elastic deformation. The invention also relates to a vehicle equipped with at least one such seat. Figure to be published with the abstract: Fig. 1

Description

VEHICLE SEAT SUSPENSION DEVICE

The invention relates to a device for suspending a vehicle seat.

Here the term seat must be understood as designating a seat of a motor vehicle, whatever the shape of the seat, whether it is intended for the driver or a passenger and whether the vehicle is a car, a van, a truck, a public works or agricultural machine.

A vehicle seat is subjected to stresses during the vehicle's movement such as vibrations and shocks due to the state of the road on which the vehicle is traveling. A vehicle seat must provide constant comfort to the occupant of the seat by absorbing vibrations and shocks, regardless of the size and weight of the occupant while providing optimal adjustment of the occupant's position in the seat. The seat must also comply in all circumstances with safety constraints in the event of a vehicle accident and ensure the integration of occupant restraints such as seat belts or airbags, frequently referred to in English as airbags. Other constraints are taken into account when making a vehicle seat, for example the weight, the number of parts, the ease of recycling of the materials used to make the seat.

To ensure the suspension of a vehicle seat in an efficient and simple manner regardless of the occupant, US-B-10 266 081 discloses a suspension device configured as a piston mounted sliding in a cylinder fixed in rails allowing the seat to slide, the piston being connected by one end to the seat. In one embodiment, the cylinder receives a non-Newtonian fluid. US-B-9 688 173 also discloses a suspension assembly suitable for seats subjected to strong oscillations and shocks such as those equipping vehicles moving on uneven terrain. Such an assembly is an active hydropneumatic suspension with an adjustment of the flow rate of the hydraulic fluid allowing the damping to be adapted to the nature of the terrain in order to maintain optimum comfort in all circumstances. Existing solutions are particularly intended for relatively heavy seats and are bulky. There is therefore a need for a vehicle seat suspension device which is simple, with a reduced number of parts, effective whatever the nature of the traffic lane and/or the occupant and/or the type of vehicle.

The invention aims to meet this need by offering a suspension device that is simple to produce and recycle, effective for all types of seats and seat occupants, comfortable whatever the vehicle's travel conditions, while ensuring optimum energy absorption in the event of a rear impact.

To this end, the invention relates to a vehicle seat comprising a frame for holding the seat and the back of said seat and a member for fixing said seat to a vehicle, at least one suspension device being positioned between said holding frame and said fixing member, characterized in that the suspension device comprises at least one deformable sphere with elastic deformation.

Thus, thanks to the invention, a seat suspension device is obtained which allows, in a simple manner, with a minimum of parts, to achieve damping in all circumstances, and therefore to ensure seating comfort for an occupant of the seat, regardless of the size and weight of the occupant thanks to the spherical shape of the device. A sphere has optimal mechanical deformation compared to other shapes while having significant mechanical strength, for example approximately twice that of a cylinder of equivalent volume. Such a suspension device offers a limited number of parts, easily recyclable and adaptable to any type of seat and/or vehicle with optimized energy absorption.

According to advantageous but not mandatory aspects of the invention, such a vehicle seat may comprise one or more of the following features:

The sphere constituting the suspension device is hollow, the internal volume of the sphere receiving a fluid.

The fluid is a compressible fluid, for example an inert gas.

The fluid is an incompressible fluid, for example an oil.

The fluid is a non-Newtonian rheo-thickening fluid.

The sphere includes in its internal volume receiving an incompressible fluid at least one dense and deformable stop.

The stop is provided with through holes.

The sphere includes in its internal volume a container receiving an incompressible fluid, the container being connected to a piston and to another container receiving a compressible fluid, separated from the incompressible fluid by a deformable membrane and a hydraulic pump, the assembly defining an active hydropneumatic suspension.

The seat base and back support member and the vehicle attachment member are formed by a single-piece metal frame with elastic behavior obtained by bending the frame.

The invention also relates to a vehicle equipped with at least one seat conforming to any one of the preceding characteristics.

The invention will be better understood and other advantages thereof will appear more clearly on reading the description which follows, given solely as a non-limiting example and with reference to the appended drawings in which:

is a three-quarter rear perspective view of a vehicle seat according to one embodiment of the invention,

is a side view, to the same scale, of the headquarters of the ,

is a side view, on a larger scale, of detail III at the , the suspension device being in a minimal damping configuration and illustrated in section,

is a side view similar to the and on the same scale, the device being in a maximum damping configuration and illustrated in section,

is a view similar to the , on the same scale, in accordance with a second embodiment of the invention,

is a view similar to the , on the same scale, in accordance with the second embodiment of the invention,

is a view similar to the , on the same scale, in accordance with a third embodiment of the invention,

is a larger scale view of detail VIII at the ,

is a schematic sectional view, on another scale, conforming to a fourth embodiment of the invention, only the device placed in the volume of the sphere being illustrated for greater readability and

is a view similar to the , at the same scale, the device being in another damping configuration.

There is an illustration of a vehicle seat 1 according to an embodiment of the invention. The seat 1 comprises a support frame 2 for the seat 3 and the backrest 4. The seat 3 and the backrest 4 are made of a recyclable material, for example a polymer such as polyurethane. Here the seat 3 and the backrest 4 are made of the same material. Alternatively, the materials are different between the seat 3 and the backrest 4. In all cases, the materials used are easy to machine by techniques known per se, for example by thermoforming, by molding or other. The support frame 2 for the seat 3 and the backrest 4 is, advantageously, a metal frame for example made of steel or aluminum. Alternatively, it is made of another material, for example a polymer or a composite material. The frame 2 is advantageously made by bending a bar, here with a circular section, so as to exhibit elastic behavior. Alternatively, the frame is obtained from a hollow tube. Alternatively, the section of the frame is square or rectangular. In all cases, the frame 2 is configured to have optimal reversible elastic behavior, both by the nature of the material used and by its configuration. Thus, the frame 2 is a single piece, monobloc, and ensures the maintenance of the seat 3 and the backrest 4 on the lateral edges L and R of the latter, therefore on the lateral edges of the seat 1. The parts of the frame 2 maintaining the seat 3 and the backrest 4 are configured globally in a U shape.

The seat 3 is held, under each of the edges G and D, by a branch 5 of a first U-shaped part with a flat bottom, referenced 6, defining the support of the seat 3. The part 6 is described with reference to the edge G of the seat 1 visible in FIGS. 1 and 2, it being understood that the edge D is identical. The branch 7 opposite the branch 5 is adapted to be fixed on the vehicle and defines, de facto, a member for fixing the seat 1 to the vehicle. The bottom 8 of this U connects two ends 9 and 10 of, respectively, the branches 5 and 7. As illustrated in , when seat 1 is unoccupied, branches 5 and 7 are spaced apart, the spacing being at its nominal value and part 6 has no elastic behavior.

A second part of the frame 2, referenced 11, is configured in a U shape with a rounded bottom. This part 11 ensures the support of the backrest 4. The branches 12, 13 of the part 11 are substantially parallel and connected by one end to a rounded bottom 14 of the part 11. The ends 15, 16 of the branches 12, 13 opposite those connected to the bottom 14 are connected to each branch 5 of the first part 6. The connection is made at the ends 17 of the branch 5 opposite those connected to the bottom 8. Thus, it is the configuration of the frame obtained by bending a bar which mainly ensures the elastic behavior of the frame.

The junction area visible at the of the ends 16 and 17 of the branches 13, 5, respectively, of the parts 11 and 6 receives at least one suspension device according to the invention. As noted in , in this embodiment of the invention, each junction zone located on the edges G and D receives an independent suspension device. Each suspension device comprises two supports 18, 19 fixed, for one referenced 18, to the junction zone of the ends 15 or 16 of the branches 12, 13 with each end 17 of each branch 5 and, for the other referenced 19, to the free ends 20, 21 of each branch 7 of the part 6. Here, the support 18 is conical, with a concave base. Alternatively, it has another geometric shape. The supports 18, 19 of each edge G, D hold between them a sphere 22 constituting the suspension device according to the invention. The holding of each sphere 22 is carried out, in one embodiment, in a non-definitive manner, in order to be able to easily change the sphere if necessary or intervene for maintenance operations.

The spheres 22 are deformable and have a reversible elastic behavior, therefore returning to their initial shapes as soon as the stress exerted on the sphere 22 ceases. The nominal diameter D of the spheres 22 is observed for a nominal spacing E between the branches 5 and 7 of the part 6 holding the seat 3 without an occupant of the seat 1, the vehicle being stationary. Such a configuration is that shown in Figures 1 and 2. Depending on the seats, the nominal diameter D of the sphere 22 is between 8 cm and 12 cm.

Each sphere 22, whether solid or not, is made of a material with reversible elastic deformation, for example an elastomer, a silicone, a composite material, a metallic material, depending on the desired elasticity. Each sphere 22 is, as a variant, made of several materials with reversible elastic deformation but all the spheres 22 are always identical. Each sphere 22 is adapted to filter the vibrations of the seat 1 and absorb the shocks and jolts felt when the vehicle is rolling on a traffic lane. The spheres 22 are also adapted for optimal energy absorption in the event of a rear impact. The impacts and jolts generate a translational movement of the seat 3 and the backrest 4 according to the double arrow F as well as vibrations of the seat 3 and/or the backrest 4. Such a translational movement has the effect of modifying the nominal spacing E between the branches 5 and 7 of the part 6. This modification is attenuated, in intensity and duration, by the deformation of the spheres 22. The vibrations undergone by the seat 1 during the rolling of the vehicle, whatever their direction, are also damped by the spheres 22. Tests carried out by the applicant have shown that a spherical shape allows for optimal mechanical deformation and in all cases greater than that of a cylinder of the same volume as the sphere, this with a mechanical resistance to crushing of the sphere approximately twice that of a cylinder of the same nature and volume as the sphere.

There illustrates on a larger scale the sphere 22 in place between the supports 18 and 19 equipping the edge G of the seat 1 as shown in the , when the diameter of the sphere 22 is nominal, the seat 1 being unoccupied and the vehicle stationary. No stress is exerted in this configuration on the sphere 22. The illustrates the case where seat 1 is occupied and a maximum stress, for example due to shocks and jolts when the vehicle is moving, is exerted on the sphere 22. The deformation of the sphere 22 results in a configuration in an ellipsoid of revolution, for example in the shape of a rugby ball. For greater readability, the reference 22 will also be used to designate the ellipsoid, therefore the deformed sphere. illustrates such a maximum deformation of the sphere 22 with a minimum spacing E1 between the branches 5 and 7 of the part 6, therefore de facto a minimum spacing between the supports 18 and 19. The elastic deformation of the sphere 22 is such that the minimum spacing E1 can be twice less than the nominal spacing E. We also note an inclination of the ellipsoid 22, the plane of symmetry at the equator P of the latter no longer being globally parallel to mean planes P18, P19 of the supports 18 and 19, as is the case in FIG. when the sphere 22 is not deformed. This means that part of the supports 18 and 19 is no longer in contact with the ellipsoid 22. Such a situation is ephemeral, of the order of a few tenths of a second, the elasticity of the sphere 22 ensuring a return if not to the nominal configuration at least to a configuration with low stress, therefore a configuration close to the nominal configuration. Both the spherical shape and the nature of the material constituting the sphere 22 ensure optimum absorption of vibrations and shocks or jolts, this in a reduced volume and with a minimum of parts. Subsequently, the invention will be described with reference to a sphere 22, in accordance with FIGS. 3 to 10 and to facilitate reading. It is understood that the invention concerns all the spheres equipping the seat 1.

In the embodiment of Figures 3 and 4, the sphere, when hollow, is advantageously filled with a fluid. The fluid is either incorporated during the manufacture of the suspension device or subsequently, a closable access to the internal volume of the sphere 22 then being provided. The use of a fluid improves the effectiveness of the damping, the fluid also participating in the absorption of shocks and jolts.

If the fluid used is compressible, i.e. a gas, for example air or an inert gas such as nitrogen. Tests have shown that using an incompressible fluid, i.e. a liquid such as an oil, liquid silicone, is more effective than using a gas, i.e. it has better behavior and better stability regardless of the driving conditions and the speed of the stress on the suspension device.

According to an advantageous embodiment, the incompressible fluid is a non-Newtonian fluid. While a Newtonian fluid has a constant viscosity independent of the stress or more precisely of the shear stress and the shear rate, a non-Newtonian fluid has a viscosity that changes when it is subjected to a stress. For certain non-Newtonian fluids, the viscosity decreases with the stress. This is the case for the sauce called ketchup, for example, which becomes more liquid when shaken. The fluid is said to be pseudoplastic or rheothinning. For other non-Newtonian fluids called rheothickening, the viscosity increases with the stress. This is the case, for example, for aqueous solutions of cornstarch. The use of a rheothickening non-Newtonian fluid allows increased comfort for the occupant of the seat 1 because such a fluid gradually hardens with the intensity of the stress, thus allowing a response of the suspension device adapted to the shocks and jolts undergone by the seat 1, this without the deformation of the sphere 22 being systematically maximum as with a Newtonian fluid. In other words, with a non-Newtonian fluid, the sphere 22 always retains a capacity for reversible elastic deformation, for a wider range of stresses, this while allowing the volume of fluid used to be reduced. Such a reduction, of the order of 30% compared to a Newtonian fluid, therefore allows the volume of the sphere 22 to be reduced, which in addition to a reduction in material costs allows the use of the device which is the subject of the invention in a minimal footprint.

The embodiment illustrated in Figures 5 and 6 describes a variant in which the sphere 22 is filled with an incompressible fluid, Newtonian or non-Newtonian. A stop 23, here configured as a cylinder with a circular base, is inserted into the volume of the sphere 22. This stop 23 is secured by one end 24 to the wall of the sphere 22, its opposite end 25 being free. The stop 23, whatever its geometric configuration, is advantageously solid and made of a deformable material, for example an elastomer or a dense polymer foam. In the absence of stress, as illustrated in , the free end 25 of the stop 23 is located in the internal volume of the sphere 22, without touching the wall of the sphere 22. When a stress is exerted on the sphere 22, the latter deforms and, as shown in , the free end 25 of the stop comes to bear on the wall of the sphere 22. The stop 23 thus limits the deformation of the sphere 22. The fact that the stop 23 is itself deformable makes it possible to absorb part of the shocks and jolts while ensuring a progressive stop of the deformation of the sphere 22, which contributes to the comfort of the occupant of the seat 1. The length and/or the nature of the stop 23 are chosen according to the maximum deformation permitted and/or the desired comfort. Alternatively, there is not one stop but several stops, identical or not, inserted in the volume of the sphere 22.

Figures 7 and 8 illustrate another variant in which the stop 23 is provided with through-orifices 26, diametrically arranged and distributed along the length of the stop 23. Thus, when the sphere 22 is filled with an incompressible fluid, whether the latter is Newtonian or non-Newtonian, the presence of the orifices 26 facilitates the circulation of the fluid through the sphere 22 by being uniformly distributed on either side of the stop 23, in particular during the deformation thereof. In addition, the circulation of the fluid through the orifices 26, according to the arrows F26, contributes to the damping. The friction of the fluid as it passes through the orifices 26 induces a dissipation of energy, due to the viscosity of the fluid. It is understood that the number of orifices 26, their shapes and dimensions, as well as the viscosity of the fluid, Newtonian or not, makes it possible to adjust the desired damping.

In Figures 9 and 10, only one device integrated into the sphere in this embodiment is illustrated in schematic section and on a larger scale for greater readability, the sphere not being shown. Here, the deformable sphere 22 is provided in the upper part, that is to say at the level of the part of the sphere 22 in contact with the support 18 of a piston 27 movable in translation according to the arrow F27 in a container 28 filled with an incompressible, Newtonian fluid 29. An end 30 of the container 28 opposite the introduction end of the piston 27 is provided with at least two non-return valves 31, 32. The valve 31 opens towards the container 28. The valve 32 opens towards a second container 33 extending the container 28 and located as close as possible to the support 19. The internal volume of the container 33 is separated into two parts, equal or not, by a sealed and deformable membrane 34, for example made of elastomer. The so-called lower part of the container 33, therefore the one located between the membrane 34 and the support 19 receives an inert gas 35, for example nitrogen. A hydraulic pump 36, known per se, is connected to the fluid 29 at the level of the container 28. Here, to facilitate reading, the container 28 is schematized by a cylindrical shape and the container 33 by a spherical shape. It should be borne in mind that the containers 28 and 33 are both non-deformable and integrated into the sphere 22, the support 18 has a configuration ensuring monitoring of the movement of the piston 27 without it coming into contact with the cylinder 28.

In the configuration illustrated in the , no stress is exerted on the seat 1. The piston 27 is in the upper part in the container 28, the fluid 29 occupying the volume of the container 28. The membrane 34 is in its initial position, not deformed. The fluid 29 is pushed back by the valve 31 of the container 33 towards the container 28, according to the arrow F31 until the fluid 35 is at its nominal pressure and no longer exerts stress on the membrane 34.

When the seat 1 experiences a shock or jolt and/or in the presence of an occupant, the supports 18 and 19 move closer together, which has the effect of moving the cylinder 27 in the container 28. The fluid 29 is pushed back towards the container 33 by passing through the valve 32 according to the arrow F32. The fluid 29 presses on the membrane 34 which deforms and compresses the fluid 35. The return to the configuration of the is then done when the stress exerted on the seat 1 decreases or stops. The hydraulic pump 36 has the function of putting and maintaining the fluid 29 at a defined pressure. In the variant illustrated in FIGS. 9 and 10, the combined use of two types of fluids makes it possible to have relatively low fluid pressure levels, generally of the order of ten times lower in value than the pressure encountered in the case of FIGS. 3 to 8. It is thus possible to use composite materials which allow the production of thinner spheres and reduced sizes.

Thanks to the invention, comfortable vehicle seats are produced, with optimum shock resistance, while being simple and light.

Claims (10)

Vehicle seat (1) comprising a support frame (2) for the seat (3) and the backrest (4) of said seat (1) and a member for fixing said seat (1) to a vehicle, at least one suspension device being positioned between said support frame (2) and said fixing member, characterized in that the suspension device comprises at least one deformable sphere (22) with elastic deformation. Vehicle seat according to claim 1, characterized in that the sphere (22) constituting the suspension device is hollow, the internal volume of the sphere receiving a fluid. Vehicle seat according to claim 2, characterized in that the fluid is a compressible fluid, for example an inert gas. Vehicle seat according to claim 2, characterized in that the fluid is an incompressible fluid, for example an oil. Vehicle seat according to claim 4, characterized in that the incompressible fluid is a rheothickening non-Newtonian fluid. Vehicle seat according to any one of claims 4 or 5, characterized in that the sphere (22) comprises in its internal volume receiving an incompressible fluid at least one dense and deformable stop (23). Vehicle seat according to claim 6, characterized in that the stop (23) is provided with through holes (26). Vehicle seat according to claim 2, characterized in that the sphere (22) comprises in its internal volume a container (28) receiving an incompressible fluid (29), the container (28) being connected to a piston (27) and to another container (33) receiving a compressible fluid (35), separated from the incompressible fluid (29) by a deformable membrane (34) and a hydraulic pump (36), the assembly defining an active hydropneumatic suspension. Vehicle seat according to any one of claims 1 to 8, characterized in that the member for holding the seat (3) and the backrest (4) of the seat (1) and the member for fixing to a vehicle are formed by a single-piece metal frame (2) with elastic behavior obtained by folding the frame. Vehicle equipped with at least one seat (1) according to any one of claims 1 to 9.