Method for designing a cushion suitable for a person

Abstract

The invention relates to a method for designing a cushion for a seat of a motor vehicle suitable for a person, the method comprising the steps of: obtaining a first pressure map representative of the pressures exerted on an accommodating surface (100) of the cushion by the person seated in the seat in a resting situation; obtaining a second pressure map representative of the pressures exerted on the accommodating surface (100) by the person in a situation under strain; obtaining a plane (P) defining a network of three-dimensional meshes for the 3D printing of the cushion. In a first region (Z1) in the immediate vicinity of the accommodating surface (100), the mesh has a rigidity corresponding to the first map (C1), and in a second region (Z2), distal relative to the accommodating surface (100), the mesh has a rigidity corresponding to the second map (02).

Description

[0001] Title of the invention: Method for designing a cushion adapted to an individual

[0002] Technical field and technological background

[0003] The present invention relates to a method for designing a cushion for a seat of a motor vehicle adapted to an individual, and in particular to a method for manufacturing by 3D printing a cushion whose plan is obtained by the design method according to the invention. The invention further relates to a computer-readable data carrier on which the plan is recorded, as well as a cushion obtained by the manufacturing method according to the invention.

[0004] Due to the great flexibility of using a 3D printer, a current trend is to manufacture a vehicle seat and backrest with this technique. Indeed, it is enough to program this 3D printer with the appropriate input parameters to obtain a seat or backrest having the desired geometry, dimensions and structure. The characteristics of this seat or backrest can be modified at will, by simply varying said input parameters. The result is a seat or backrest made up of a network of three-dimensional meshes. The characteristics of this network can vary with the depth of said seat or backrest so that the rigidity of the seat is greater in the vicinity of a seat frame than near the cushion receiving surface, this to improve comfort for the seat occupant.

[0005] Seat design is even more important for a driver of a racing vehicle intended to be driven on a circuit, as the driver's comfort impacts his performance in a race.

[0006] Therefore, an improvement in the comfort of an individual in a seat of a motor vehicle, in particular of a motor racing driver in a seat of a racing vehicle, is sought.

[0007] Summary of the invention

[0008] The subject of the invention is a method for designing a cushion for a seat of a motor vehicle adapted to an individual, comprising the steps of:

[0009] - obtain a first pressure map representative of pressures exerted on a receiving surface of said cushion by the individual installed in said seat, in a resting situation;

[0010] - obtain a second pressure map representative of pressures exerted on the receiving surface of said cushion by the individual installed in said seat, in a situation under stress;

[0011] - obtaining a plan defining a three-dimensional mesh network for 3D printing of said cushion, such that in a first zone in the immediate vicinity of the receiving surface of the cushion, the mesh network has a rigidity corresponding to the first pressure map of the individual, and in a second zone, distal to the receiving surface of the cushion, the mesh network has a rigidity corresponding to the second pressure map of the individual.

[0012] In particular, in the resting situation the individual is immobile on the seat. This is particularly the case when the vehicle is stationary or when the occupant is not manipulating the vehicle's control means. In particular, in the stress situation, the occupant exerts a force on the seat, for example because he is dynamic on the seat, or because he manipulates the vehicle's control means, such as accelerator or brake pedals, or is subjected to acceleration. Thanks to the first and second maps, the cushion plane is personalized with the characteristics of the individual intended to occupy the seat. Thus, the deformation of the cushion in a resting situation or in a stress situation is specific to the individual, which improves his comfort.

[0013] According to one embodiment, in the stress situation the individual exerts pressure on the vehicle's control means.

[0014] According to one embodiment, in the situation under stress a suspension system of the vehicle is at the stop.

[0015] According to one embodiment, the step of obtaining the first or second mapping comprises installing the individual against a two-dimensional matrix of pressure sensors, acquiring the pressure mapping, comprising a 2D map of the pressures detected by said matrix. According to one embodiment, the stiffness of the mesh network is obtained by adapting a thickness of an elementary mesh strand of the mesh network. According to one embodiment, the stiffness of the mesh network varies progressively from the first zone to the second zone.

[0016] According to one embodiment, obtaining the plan of said cushion comprises determining a local rigidity of the mesh network so as to absorb a local pressure exerted by the individual.

[0017] According to one embodiment, the plane of the cushion is configured such that the cushion comprises transverse portions extending from the receiving surface of the cushion towards a surface of the cushion opposite said receiving surface, only a part of said transverse portions comprising the first zone and the second zone.

[0018] According to a variant, the transverse portions comprising the first zone and the second zone correspond to zones of the second map in which the pressure is greater than a threshold.

[0019] The invention further relates to a computer-readable data carrier on which is recorded a plan defining a three-dimensional mesh network for 3D printing obtained by the design method according to the invention. The invention also relates to a method for manufacturing by 3D printing a cushion for a seat of a motor vehicle, using a plan obtained by the design method according to the invention.

[0020] The invention also relates to a cushion for a seat of a motor vehicle obtained by the manufacturing method according to the invention.

[0021] Brief description of the figures

[0022] The following description with reference to the attached drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented. In the attached figures:

[0023] [Fig. 1] Figure 1 represents a first pressure map, [Fig. 2] Figure 2 represents a second pressure map, [Fig. 3] Figure 3 partially represents a plan for a 3D printing of a cushion,

[0024] [Fig. 4] Figure 4 includes successive schematic views of a cushion, [Fig. 5] Figure 5 represents an example of a sensor matrix,

[0025] [Fig. 6] Figure 6 is a schematic view of a cushion,

[0026] [Fig. 7] Figure 7 shows a legend of the maps in Figures 1 and 2.

[0027] Detailed description

[0028] An example of a method for designing a cushion for a motor vehicle seat adapted to an individual will be described with reference to the figures. The cushion may be intended to form a seat or a backrest of the seat. The term "cushion" means in particular one or more constituent elements of a cushion.

[0029] The seat includes in particular a succession of technical elements. For example, the seat includes a rigid structure determining the general shape of the seat. A suspension layer can be positioned on this rigid structure to provide flexible support for the cushion. Alternatively, the cushion can rest directly on the rigid structure or on any other intermediate element between the rigid structure and the cushion. The cushion itself can be covered with a garment, for example made of natural or synthetic textile material, at least on its surface in contact with the individual. The receiving surface of the cushion is the face of the cushion on which the occupant rests when installed in the seat.

[0030] The design process allows for a plan to be obtained for 3D printing of the cushion, which is adapted to the individual intended to occupy the seat. To this end, a first and a second pressure map are produced, which are representative of the pressures exerted on the receiving surface of the cushion when the individual is installed in the seat.

[0031] The first pressure map is acquired in a resting situation. An example of a first C1 map acquired for a cushion forming a seat base is illustrated in Figure 1. In particular, the example of a first C1 map is acquired when the individual is inactive on the seat, in particular when he is not manipulating vehicle control means, such as, for example, brake or accelerator pedals or a steering wheel.

[0032] The second pressure map is acquired in a situation under stress. An example of a second C2 map acquired for the cushion forming a seat base is illustrated in Figure 2. In particular, the second C2 map is acquired in a situation in which the individual exerts pressure on an accelerator or brake pedal of the vehicle. Other means of controlling the vehicle may be taken into account, alternatively or in combination with the accelerator or brake pedals, such as for example the steering wheel of the vehicle. For example, when the actuations of several control means are taken into account, the second map may comprise average values ​​or maximum values ​​acquired during the actuations of the control means.

[0033] The pressures exerted by the individual installed on the cushion are represented by hatched areas. Figure 7 gives the legend of the hatched areas. They represent increasing pressure ranges as shown in Figure 7. The receiving surface 100 of the cushion may comprise different areas which are distinguished by the part of the individual coming against them. The receiving surface 100 may comprise a left lateral area 110g and a right lateral area 110d against which the flanks of the individual come to bear, a front central area 120f receiving the thighs of the individual, and a rear central area 120r against which the ischial bones of the individual come. The measured pressures range in particular from 0.13 to 2.67 daN / cm 2 .

[0034] From these maps C1, C2, a plan of the cushion is obtained, an example of which is partially represented in figure 3. The plane P defines a network of three-dimensional meshes for 3D printing of the cushion. In particular, the plane P is characterized among other things by the shape of the elementary meshes, their dimensions, such as the height or the side of the elementary mesh, or the width of the strands, and the location in space of the elementary mesh. In a first zone Z1, in the immediate vicinity of the receiving surface 100, the network of meshes has a rigidity corresponding to the first pressure map C1 of the individual. In a second zone Z2, distal to the receiving surface 100, the network of meshes has a rigidity corresponding to the second pressure map C2 of the individual.In particular, the second zone Z2 is in the immediate vicinity of a face of the cushion which is opposite the receiving surface 100, this face coming in particular against a rigid structure of the seat. The advantage of the design method will be better understood by referring to Figure 4, which represents schematic views of a cushion obtained from the design method. In an initial situation a), the individual will sit on the cushion. The zones Z1, Z2 of the cushion are not yet deformed. In a resting situation illustrated in view b), the individual is installed on the cushion and is relatively immobile. The first zone Z1 deforms to absorb the weight of the individual. In a situation illustrated in view c), the individual exerts a force compared to the previous situation, for example due to an actuation of the control means of the motor vehicle. The first zone Z1 can then reach its deformation limit.But, because the rigidity of the second zone Z2 is adapted according to the second mapping C2, the second zone C2 is still deformable and can therefore absorb additional pressures exerted by the individual.

[0035] In the situation under stress, the vehicle's suspension system may be at its limit. In particular, the vehicle's suspension is at its limit when the suspension system is no longer able to absorb a force or a vibration due to its amplitude. The inventors have noted that, given the high speed in a driving situation, it may happen that the suspension system of a racing vehicle traveling on a circuit reaches its limit when encountering a feature on the track. A feature is, for example, a hole or a bump on the track of the circuit. The driver then feels a sudden acceleration. Because the second zone is designed according to the second mapping, the cushion can be designed so that, even in a situation in which the suspension system is under stress, the cushion still has elasticity allowing it to deform to compensate for pressure exerted by the driver.The comfort of the individual while driving the vehicle is improved. The situation where the system is at its limit can be taken into account independently or in combination with a situation in which the individual manipulates the vehicle's actuation means.

[0036] Preferably, the first C1 and second C2 maps are obtained using a two-dimensional matrix of pressure sensors 150 illustrated for example in Figure 5. The pressure sensor 150 is installed on the seat that will be mounted in the vehicle or a seat representative of that which will be installed in the vehicle. Thanks to the matrix of sensors 150, the pressures exerted by the individual in a real situation can be recorded. However, the maps C1, C2 could be obtained differently, for example by a simulation based on a model of the individual's body and a model of the seat. In particular, the plan is obtained using a computer. In particular using software dedicated to the generation of three-dimensional mesh networks for 3D printing. For example, the software tools Grasshoper or N topology are known.The first C1 mapping or the second C2 mapping are then parameters used by the computer, in particular the software, to generate the three-dimensional mesh network.

[0037] The stiffness of the mesh network can be determined based on the shape of the unit cell, or the dimensions of the unit cell, in particular those of the voxel which is the cube in which the unit cell is inscribed. However, preferably, the stiffness of the mesh network is adapted by adjusting the strand thickness of the unit cell. A variation in the strand thickness is easier to implement during 3D printing of the cushion. Thus, in particular, the unit cell in the second zone Z2 has a strand thickness greater than the strand thickness of the unit cell in the first zone Z1.

[0038] In particular, the other characteristics of the unit cell remain identical across the mesh network. Thus, in particular, the shape of the unit cell is a truncated octahedron, but other unit cell shapes compatible with 3D printing are possible. In particular, the voxel has a side between 1 and 1.5 cm, for a cushion with a thickness between 1 and 4 cm.

[0039] Preferably, the stiffness of the mesh network varies progressively from the first zone Z1 to the second zone Z2. Thus, the mesh network may comprise one or more intermediate zones Z3 between the first zone Z1 and the second zone Z2, in which the thickness of the strand is between the thickness of the strand in the first zone Z1 and that in the second zone Z2, the strand thickness increasing from the first zone Z1 to the second zone Z2. Thus, the occupant of the seat does not perceive any jolts in the damping implemented by the cushion. Preferably, the local stiffness of the mesh network is adapted so as to absorb local pressure exerted by the individual. In other words, the local values ​​of the first mapping C1 and the second mapping C2 are used to determine the local stiffness in the first zone Z1 and the second zone Z2 of the mesh network. Thus, the comfort of the occupant of the seat is improved.Alternatively, the first zone Z1 and the second zone Z2 may each have a uniform rigidity with respect to the areas 110g, 110d, 120f, 120r of the receiving surface 100 of the cushion. The rigidities with respect to each area 110g, 110d, 120f, 120r are determined to compensate for an average pressure exerted on the area obtained from the first mapping C1 and an average pressure exerted on the area obtained from the second mapping C2.

[0040] In particular, as for example schematically illustrated in figures 3 and 6, the maps C1, C2 make it possible to provide the first zone Z1 and the second zone Z2 only on transverse portions B of the cushion where this is useful, that is to say in transverse portions B of the cushion where the difference between the pressure in the first map C1 and the pressure in the second map C2 is significant, in particular greater than a threshold. In particular, the other transverse portions A, C have a uniform rigidity when the difference between the pressure in the first map C1 and the pressure in the second map C2 is not significant, in particular is less than a threshold. The transverse portions A, B, C extend from the receiving surface 100 of the cushion towards a surface of the cushion opposite said receiving surface. The design method makes it possible to finely adapt the plane of the cushion.The 3D printing then used to manufacture the cushion is sufficiently precise to allow implementation of the cushion plan. Furthermore, preferably, the first zone Z1 and the second zone Z2 are provided in a transverse portion B if the corresponding pressure(s) in the second mapping C2 are greater than a threshold. In particular, such a threshold is equal to a percentage of the maximum pressure of the second mapping C2, for example 90%, 80%, 70% or 60% of the maximum pressure of the second mapping C2. For example, referring to Figures 1 and 2, it is noted that the highest differences between the first mapping C1 and the second mapping C2 and the highest pressure values ​​in the second mapping C2 are found in the rear central area 120r, in particular at the level of the individual's ischial bones.Thus, the first Z1 and the second Z2 zone can be provided only opposite the rear central area 120r of the receiving surface 100. This saves material when 3D printing the cushion.

[0041] The plane P defining the three-dimensional mesh network can be stored in a computer-readable data medium, in particular in the form of digital data. The medium can then be read by a 3D printer to manufacture the cushion according to the plane P.

[0042] The 3D printer can then produce the cushion using an additive manufacturing process, including a succession of deposition and polymerization of layers of material along the plane P.

[0043] The cushion can then be positioned on a seat of a motor vehicle, in particular a motor racing vehicle. In a driving situation, the seat is occupied in particular by the individual for whom the plan P was designed. This individual is in particular a motor racing driver.

[0044] The mapping examples C1, C2 in the figures were acquired on a seat cushion, but maps acquired on a seat back cushion could have been used to describe the design process. Preferably, the maps related to the seat cushion and those related to the seat back are acquired at the same time. For example, when the individual presses a brake or accelerator pedal, the individual unloads the seat cushion and loads the backrest.

[0045] The individual is in particular a human subject, for example a racing driver or any other driver of a motor vehicle.

Claims

Claims

1. A method of designing a cushion for a seat of a motor vehicle adapted to an individual, comprising the steps of: - obtaining a first pressure map (C1) representative of the pressures exerted on a receiving surface (100) of said cushion by the individual installed in said seat, in a resting situation; - obtaining a second pressure map (C2) representative of the pressures exerted on the receiving surface (100) of said cushion by the individual installed in said seat, in a situation under stress; - obtaining a plane (P) defining a three-dimensional mesh network for 3D printing of said cushion, such that in a first zone (Z1) in the immediate vicinity of the receiving surface (100) of the cushion, the mesh network has a rigidity corresponding to the first pressure mapping (C1) of the individual, and in a second zone (Z2), distal to the receiving surface (100) of the cushion, the mesh network has a rigidity corresponding to the second pressure mapping (C2) of the individual.

2. Method according to claim 1, in which, in the situation under stress, the individual exerts pressure on control means of the vehicle.

3. Method according to claim 1 or 2, in which, in the situation under stress, a suspension system of the vehicle is at the stop.

4. Method according to one of the preceding claims, in which the step of obtaining the first (C1) or the second (C2) mapping, comprises installing the individual against a two-dimensional matrix of pressure sensors (150), acquiring the pressure mapping, comprising a 2D map of the pressures detected by said matrix.

5. Method according to one of the preceding claims, in which the rigidity of the mesh network is obtained by adapting a thickness of an elementary mesh strand of the mesh network.

6. Method according to one of the preceding claims, in which the rigidity of the mesh network varies progressively from the first zone (Z1) to the second zone (Z2).

7. Method according to one of the preceding claims, in which obtaining the plane (P) of said cushion comprises determining a local rigidity of the mesh network so as to absorb a local pressure exerted by the individual.

8. Method according to one of the preceding claims, wherein the plane (P) of the cushion is configured so that the cushion comprises transverse portions (A, B, C) extending from the receiving surface (100) of the cushion towards a surface of the cushion opposite said receiving surface (100), only a part (B) of said transverse portions comprising the first zone (Z1) and the second zone (Z2).

9. Computer-readable data carrier on which is recorded a plane (P) defining a three-dimensional mesh network for 3D printing obtained by the method according to one of the preceding claims.

10. Method of manufacturing by 3D printing a cushion for a seat of a motor vehicle, using a plane (P) obtained by the method according to one of claims 1 to 8.

11. Cushion for a seat of a motor vehicle obtained by the method according to the preceding claim.

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