Method for designing a cushion adapted to an individual

Abstract

The invention relates to a method for designing a cushion for a motor vehicle seat adapted to an individual, comprising the steps of: obtaining a first pressure map representative of the pressures exerted on a receiving surface (100) of said cushion by the individual seated in said seat, in a resting state; obtaining a second pressure map representative of the pressures exerted on the receiving surface (100) by the individual, in a stress state; obtaining a plane (P) defining a three-dimensional mesh network for 3D printing said cushion. In a first zone (Z1) in the immediate vicinity of the receiving surface (100), the mesh network exhibits a rigidity corresponding to the first map (C1), and in a second zone (Z2), distal to the receiving surface (100), the mesh network exhibits a rigidity corresponding to the second map (C2).Figure for the summary: Figure 3 [Fig. 1].

Description

Title of the invention: Method for designing a cushion adapted to an individual. Technical field and technological background

[0001] The present invention relates to a method for designing a cushion for a motor vehicle seat adapted to an individual, and in particular a method for manufacturing a cushion by 3D printing, the design of which is obtained by the design method according to the invention. The invention further relates to a computer-readable data carrier on which the design is recorded, as well as a cushion obtained by the manufacturing method according to the invention.

[0002] Due to the great versatility of 3D printing, a current trend is to manufacture vehicle seat cushions and backrests using this technique. Indeed, it is simply a matter of programming the 3D printer with the appropriate input parameters to obtain a seat or backrest with the desired geometry, dimensions, and structure. The characteristics of this seat or backrest can be modified at will by simply varying these input parameters. The resulting seat or backrest consists of a network of three-dimensional meshes. The characteristics of this network can vary with the depth of the seat or backrest so that the seat's rigidity is greater near the seat frame than near the cushion's surface, thus improving occupant comfort.

[0003] The design of the seat is even more important for a racing vehicle driver intended to drive on a circuit, because the driver's comfort impacts his performance in a race.

[0004] It is therefore sought to improve 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. Summary of the invention

[0005] The invention relates to a method for designing a cushion for a seat of a motor vehicle adapted to an individual, comprising the steps of: - obtaining 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; - 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; - obtain a plan defining a three-dimensional mesh network for a 3D printing of said cushion, so 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.

[0006] In particular, in the resting state, the individual is stationary in the seat. This is especially the case when the vehicle is stopped or when the occupant is not operating any vehicle controls. In particular, in the stress state, the occupant exerts force on the seat, for example, because they are actively moving in the seat, either by operating vehicle controls such as the accelerator or brake pedals, or by being subjected to acceleration. Thanks to the first and second mappings, the cushion's shape is customized to the characteristics of the individual intended to occupy the seat. Thus, the cushion's deformation in a resting state or in a stress state is specific to the individual, thereby improving their comfort.

[0007] According to one embodiment, in the situation under effort the individual exerts pressure on vehicle control means.

[0008] According to one embodiment, in the situation under stress a vehicle suspension system is at its limit.

[0009] According to one embodiment, the step of obtaining the first or second mapping includes the installation of the individual against a two-dimensional matrix of pressure sensors, the acquisition of the pressure mapping, including a 2D map of the pressures detected by said matrix.

[0010] According to one embodiment, the rigidity of the mesh network is obtained by adapting a thickness of an elementary mesh strand of the mesh network.

[0011] According to one embodiment, the rigidity of the mesh network varies progressively from the first zone to the second zone.

[0012] According to one embodiment, obtaining the plan of said cushion includes determining a local rigidity of the mesh network so as to absorb a local pressure exerted by the individual.

[0013] According to one embodiment, the cushion plan is configured so that the cushion includes transverse portions extending from the receiving surface of the cushion to a surface of the cushion opposite said receiving surface, only a part of said transverse portions comprising the first zone and the second zone.

[0014] According to one variant, the cross portions comprising the first zone and the second zone correspond to areas of the second map in which the pressure is greater than a threshold.

[0015] The invention further relates to a computer-readable data carrier on which is recorded a plan defining a three-dimensional mesh network for a 3D print obtained by the design process according to the invention.

[0016] The invention also relates to a method of manufacturing by 3D printing a cushion for a seat of a motor vehicle, using a plan obtained by the design process according to the invention.

[0017] The invention also relates to a cushion for a seat of a motor vehicle obtained by the manufacturing process according to the invention. Brief description of the figures

[0018] The following description, with reference to the accompanying drawings, given by way of non-limiting examples, will clearly explain what the invention consists of and how it can be implemented. In the accompanying figures:

[0019] [Fig. 1] Fig. 1 represents a first pressure map,

[0020] [Fig.2] Fig.2 represents a second pressure map,

[0021] [Fig.3] Fig.3 partially represents a plan for a 3D printing of a cushion,

[0022] [Fig.4] Fig.4 comprises successive schematic views of a cushion,

[0023] [Fig.5] Fig.5 represents an example of a sensor matrix,

[0024] [Fig.6] Fig.6 is a schematic view of a cushion,

[0025] [Fig. 7] The [Fig. 7] shows a legend of the maps of figures 1 and 2. Detailed description

[0026] 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. The term "cushion" includes, in particular, one or more constituent elements of a cushion.

[0027] The seat includes, in particular, a series of technical elements. For example, the seat includes a rigid structure that determines its overall shape. A suspension system may be positioned on this rigid structure to provide flexible support for the cushion. Alternatively, the cushion may rest directly on the rigid structure or on any other intermediate element between the rigid structure and the cushion. The cushion itself may be covered with a material, for example, natural or synthetic textile, at least on the surface in contact with the individual. The cushion's contact surface is the side of the cushion against which the occupant rests when seated in the seat.

[0028] The design process makes it possible to obtain a plan for 3D printing the cushion, which is adapted to the individual intended to occupy the seat. To this end, a first and second pressure map are created, which are representative of the pressures exerted on the cushion's receiving surface when the individual is seated in the seat.

[0029] The first pressure map is acquired in a resting state. An example of the first Cl map acquired for a seat cushion is illustrated in [Fig. 1]. In particular, the example of the first Cl map is acquired when the individual is inactive in the seat, specifically when they are not manipulating vehicle controls, such as brake or accelerator pedals or a steering wheel.

[0030] The second pressure map is acquired under stress conditions. An example of a second C2 map acquired for the seat cushion is illustrated in [Fig. 2]. In particular, the second C2 map is acquired when the individual applies pressure to the vehicle's accelerator or brake pedal. Other vehicle control means may be considered, either alternatively or in combination with the accelerator or brake pedals, such as the vehicle's steering wheel. For example, when actuations of several control means are considered, the second map may include average or maximum values ​​acquired during the actuations of the control means.

[0031] The pressures exerted by the individual positioned on the cushion are represented by hatched areas. Figure 7 provides the key for the hatched areas. They represent pressure ranges increasing as shown in Figure 7. The cushion's contact surface 100 may comprise different areas distinguished by the part of the individual against them. The contact surface 100 may include a left lateral area 110g and a right lateral area 110d against which the individual's flanks rest, a central front area 120f against which the individual's thighs rest, and a central rear area 120r against which the individual's ischial tuberosities rest. The measured pressures range from 0.13 to 2.67 daN / cm².

[0032] From these Cl, C2 maps, a plan of the cushion is obtained, an example of which is partially shown in [Fig. 3]. The P plan defines a three-dimensional mesh network for 3D printing the cushion. In particular, the P plan is characterized, among other things, by the shape of the elementary meshes, their dimensions, such as the height or side of the elementary mesh, or the width of the strands, and the location of the elementary mesh in space.

[0033] In a first zone Z1, in the immediate vicinity of the receiving surface 100, the mesh network exhibits a rigidity corresponding to the individual's first pressure map C1. In a second zone Z2, distal to the receiving surface 100, the mesh network exhibits a rigidity corresponding to the individual's second pressure map C2. In particular, the second zone Z2 is in the immediate vicinity of a face of the cushion that is opposite the receiving surface 100, this face specifically coming against a rigid structure of the seat.

[0034] The advantage of the design method will be better understood by referring to [Fig. 4], which shows schematic views of a cushion produced by the design method. In an initial situation a), the individual sits on the cushion. Zones Z1 and Z2 of the cushion are not yet deformed. In a resting situation illustrated in view b), the individual sits on the cushion and is relatively still. 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 the activation of the vehicle's controls. The first zone Z1 can then reach its deformation limit.However, 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] Under stress, the vehicle's suspension system may reach its limit. Specifically, the vehicle's suspension reaches its limit when the suspension system is no longer able to absorb a force or vibration due to its amplitude. The inventors observed that, given the high speeds involved in driving, the suspension system of a race car traveling on a track may reach its limit when encountering a feature on the track. Such a feature could be, for example, a pothole or a bump on the track. The driver then experiences a sudden acceleration.

[0036] Because the second zone is designed according to the second mapping, the cushion can be designed so that, even in a situation where the suspension system is under stress, the cushion still exhibits sufficient elasticity to deform and compensate for pressure exerted by the driver. This improves the driver's comfort while the vehicle is in motion. The situation where the system reaches its limit can be considered independently or in combination with a situation where the driver is manipulating the vehicle's actuation means.

[0037] Preferably, the first Cl and second C2 maps are obtained using a two-dimensional matrix of pressure sensors 150, illustrated for example in [Fig. 5]. The pressure sensor 150 is installed on the seat that will be mounted in the vehicle or a seat representative of the one that will be installed in the vehicle. Thanks With the 150 sensor array, the pressures exerted by the individual in a real-world situation can be recorded. However, the Cl, C2 maps could be obtained differently, for example by a simulation based on a model of the individual's body and a model of the seat.

[0038] In particular, the plan is obtained using a computer. Specifically, using software dedicated to generating three-dimensional mesh networks for 3D printing. Examples include the software tools "Grasshoper" or "N topology" (registered trademarks). The first map Cl or the second map C2 are then parameters used by the computer, specifically the software, to generate the three-dimensional mesh network.

[0039] The stiffness of the mesh network can be determined based on the shape of the elementary mesh, or the dimensions of the elementary mesh, particularly those of the voxel, which is the cube in which the elementary mesh is inscribed. However, preferably, the stiffness of the mesh network is adjusted by modifying the strand thickness of the elementary mesh. Varying the strand thickness is easier to implement during the 3D printing of the cushion. Thus, in particular, the elementary mesh in the second zone Z2 has a greater strand thickness than the strand thickness of the elementary mesh in the first zone ZI.

[0040] In particular, the other characteristics of the unit cell remain identical throughout the network of cells. Thus, notably, 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 length between 1 and 1.5 cm, for a cushion thickness between 1 and 4 cm.

[0041] Preferably, the rigidity of the mesh network varies progressively from the first zone ZI to the second zone Z2. Thus, the mesh network may include one or more intermediate zones Z3 between the first zone ZI and the second zone Z2, in which the strand thickness is between the strand thickness in the first zone ZI and that in the second zone Z2, with the strand thickness increasing from the first zone ZI to the second zone Z2. Therefore, the seat occupant does not perceive any jolts in the damping provided by the cushion.

[0042] Preferably, the local stiffness of the mesh network is adapted to absorb local pressure exerted by the individual. In other words, the local values ​​of the first map C1 and the second map 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 seat occupant is improved. Alternatively, the first zone Z1 and the second zone Z2 can each have a uniform stiffness with respect to areas 110g, HOd, 120f, 120r of the cushion's receiving surface 100. The stiffnesses with respect to each area 110g, 11 Od, 120f, 120r are determined to compensate for an average pressure exerted on the area obtained from the first mapping Cl and an average pressure exerted on the area obtained from the second mapping C2.

[0043] In particular, as schematically illustrated in Figures 3 and 6, the maps Cl and C2 allow the first zone ZI and the second zone Z2 to be defined only on transverse portions B of the cushion where this is useful, i.e., in transverse portions B of the cushion where the difference between the pressure in the first map Cl and the pressure in the second map C2 is significant, in particular, greater than a threshold. In particular, the other transverse portions A and C have uniform stiffness when the difference between the pressure in the first map Cl and the pressure in the second map C2 is not significant, in particular, is less than a threshold. The transverse portions A, B, and C extend from the receiving surface 100 of the cushion to a surface of the cushion opposite said receiving surface. The design process allows for fine-tuning the cushion's shape.The 3D printing process subsequently used to manufacture the cushion is precise enough to allow for the implementation of the cushion design.

[0044] Furthermore, preferably, the first zone ZI and the second zone Z2 are provided in a transverse portion B if the corresponding pressure(s) in the second map C2 are greater than a threshold. In particular, such a threshold is equal to a percentage of the maximum pressure of the second map C2, for example, 90%, 80%, 70%, or 60% of the maximum pressure of the second map C2. For example, with reference to Figures 1 and 2, it can be seen that the greatest differences between the first map C1 and the second map C2, and the highest pressure values ​​in the second map C2, are found in the central rear area 120r, specifically at the level of the individual's ischial tuberosities. Thus, the first ZI and the second Z2 zone can be provided only opposite the central rear area 120r of the receiving surface 100. This saves material during the 3D printing of the cushion.

[0045] The plane P defining the three-dimensional mesh network can be stored in a computer-readable data medium, particularly 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.

[0046] The 3D printer can then produce the cushion by an additive manufacturing process, including in particular a succession of deposition and polymerization of layers of material along the plane P.

[0047] The cushion can then be positioned on a seat of a motor vehicle, in particular a racing car. When in motion, the seat is notably occupied by the individual for whom plan P was designed. This individual is notably a race car driver.

[0048] The Cl, C2 mapping examples in the figures were acquired on a seat cushion, but mappings acquired on a seat back cushion could have been used to describe the design process. Preferably, the mappings related to the seat and those related to the seat back are acquired simultaneously. For example, when the individual presses a brake or accelerator pedal, the individual unloads the seat and loads the back.

[0049] The individual is in particular a human subject, for example a racing driver or any other driver of a motor vehicle.

Claims

Demands

1. Method for designing a cushion for a motor vehicle seat 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 stress situation;- obtain a plan (P) defining a three-dimensional mesh network for a 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 map (Cl) 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 map (C2) of the individual.;

2. A method according to claim 1, wherein, in the stress situation, the individual exerts pressure on vehicle control means.

3. Method according to claim 1 or 2, wherein, in the situation under stress, a vehicle suspension system is at its limit.

4. A method according to any one of the preceding claims, wherein the step of obtaining the first (C1) or second (C2) mapping, comprises the installation of the individual against a two-dimensional matrix of pressure sensors (150), the acquisition of the pressure mapping, comprising a 2D map of the pressures detected by said matrix.

5. A method according to any one of the preceding claims, wherein the rigidity of the mesh network is obtained by adapting a thickness of an elementary mesh strand of the mesh network.

6. A method according to any one of the preceding claims, wherein the stiffness of the mesh network varies progressively from the first zone (Z1) to the second zone (Z2).

7. A method according to any one of the preceding claims, wherein obtaining the plane (P) of said cushion includes determining a local stiffness of the mesh network so as to absorb a local pressure exerted by the individual.

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

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

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

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

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