How to produce airless tires using additive manufacturing

Abstract

1. An additive manufacturing method for a carcass (24) intended to produce an airless tire (1), the additive manufacturing method comprising: implementing an additive manufacturing machine (20) that produces multiple layers of structural elements (25) of the carcass (24) in any plane XY perpendicular to the axis of rotation of the carcass (24) by depositing beads of soluble printing material, the beads of each structural element (25) having portions that interpenetrate with the beads of each adjacent structural element (25) in any plane XY.

Description

[Technical Field]

[0001] The present invention relates to the field of methods for manufacturing airless tires intended to be mounted on vehicles.

[0002] Specifically, the present invention relates to an additive manufacturing method employing a 3D printer to produce airless tires by depositing malleable printing material in successive layers through a nozzle. [Background technology]

[0003] Generally, a printing press includes a chamber defined by walls forming an enclosure within which is located a platform for supporting the part to be printed and a nozzle for dispensing material for forming said part. A drive system is provided that includes a lift for vertically moving the platform or the nozzle to enable the part shape to be formed, and intersecting translational-displacement stages for horizontally manipulating either the platform or the nozzle to dispense material for forming the part.

[0004] Such a printing press is described, inter alia, in US Pat. No. 6,722,872.

[0005] Airless tires, or more generally tires that do not use inflation gas, are tires that support loads by means of structural elements forming a carcass and have performance aspects comparable to those of conventional tires that are under internal pressure of gas, typically air. Airless tires mounted on a hub or rim are sometimes called "non-pneumatic elastic wheels". [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 6,722,872 [Patent Document 2] US Patent Application Publication No. 2022 / 0194129 [Patent Document 3] International Publication No. 2008 / 136099 [Patent Document 4] U.S. Patent No. 9,908,369 [Patent Document 5] Japanese Patent Publication No. 2022-034665 Summary of the Invention

[0007] In the following text, circumferential or longitudinal direction refers to the direction of rotation of the tire, axial or lateral direction refers to the direction parallel to the tire's axis of rotation, and radial direction refers to the direction perpendicular to the tire's axis of rotation.

[0008] Airless tires generally have the following characteristics: a carcass formed by structural elements and intended to cooperate with a rim or a hub; a tread intended to cooperate with the carcass to transmit the rolling forces to said carcass and to wear down to ensure the grip of the tire on the ground; Includes.

[0009] The carcass is, from the radially inner side to the radially outer side, - a support structure intended to at least partially structurally support a load; - a shear band intended to transmit the running forces to the supporting structure by shear and to contribute at least partially to the support of the load; Includes.

[0010] The support structure is generally radially arranged from inner to outer: - a radially inner membrane intended to be fixed to the rim or hub by connecting means; - a plurality of radial elements or spokes intended to be fixed to the radial inner membrane and the shear band by connecting means; However, the support structure does not generally define a sealed internal cavity intended to contain pressurized gas as in conventional tires, and therefore, a non-pneumatic tire does not need to have a sealed connection to a rim or hub.

[0011] In known embodiments, the shear bands extend radially from inner to outer: - a radially intermediate membrane associated with the support structure; - a plurality of shear elements; a radially outer membrane intended to receive the tread and connected to the radial intermediate membrane by a plurality of shear elements; Includes.

[0012] Generally, the tread is secured to the radially outer membrane of the shear band by securing means which may be, for example, adhesive bonding means or hooping means.

[0013] The carcass therefore has a number of elements referred to as structural elements, which may include, for example, a radial inner membrane, a number of spokes, a radial intermediate membrane, a number of shear elements, and a radial outer membrane.

[0014] The method of manufacturing an airless tire carcass, known to those skilled in the art, is to first manufacture the various structural elements separately and then assemble them according to an assembly method and precise positioning method, which can be held in place using different methods, such as gluing, riveting, bolting, crimping or ultrasonic welding.

[0015] Such methods of assembling airless tires are described, for example, in US Patent Application Publication No. 2022 / 0194129 A1, WO 2008 / 136099 A1, and US Patent No. 9,908,369 B2.

[0016] Although such a method allows the manufacture of airless tires, it has drawbacks, particularly related to the poor adhesion between the various elements that make up this carcass.

[0017] Furthermore, the manufacturing quality of such carcasses for producing airless tires is not always satisfactory, and the geometric size variations associated with the manufacturing of each structural element, combined with positioning variations in the assembly method, can adversely affect the overall quality of the airless tire and its performance aspects.

[0018] Furthermore, the assembly method is rather complicated, requiring numerous interventions to position the various structural elements, which entails high manufacturing costs.

[0019] Other methods for producing airless tire carcasses are known to those skilled in the art, using molding processes to produce the different structural elements, as described, for example, in JP 2022-034665 A.

[0020] These methods of manufacturing structural elements by molding require the manufacture of expensive tools such as molds and are often unable to produce the complex geometric shapes required for the manufacture of structural elements for the carcass of airless tires.

[0021] The present invention therefore aims to provide a manufacturing method that overcomes the above-mentioned drawbacks and allows for the simple manufacture of an airless tire carcass at low cost, making it possible to use a wide range of materials while ensuring excellent reproducibility in the manufacture of the carcass of an airless tire and perfect adhesion between its various structural elements.

[0022] The subject of the present invention is a method for additively manufacturing a carcass of an airless tire for a vehicle, employing an additive manufacturing machine including a manufacturing platform perpendicular to the axis of rotation of the carcass having an axial direction Z, and a nozzle movable along the axial direction Z in any circumferential plane XY perpendicular to the axial direction Z, said additive manufacturing method comprising: (a) Beads such as: a radial inner membrane bead having a first width, intended to produce a radial inner membrane of the carcass; - a radial interlayer bead having a second width, intended to produce a radial interlayer of the carcass; a radial outer membrane bead having a third width, intended to produce a radial outer membrane of the carcass; - a plurality of spoke beads each having a fourth width, intended to produce a plurality of spokes connecting a radial inner membrane to a radial intermediate membrane, each having at least one first zone interpenetrating the radial inner membrane bead with a first arc length and a first maximum thickness along the radial direction, and at least one second zone interpenetrating the radial intermediate membrane bead with a second arc length and a second maximum thickness along the radial direction; - a plurality of shear element beads each having a fifth width, intended to produce a plurality of shear elements connecting a radial intermediate membrane to a radial outer membrane, each shear element bead having at least one third zone interpenetrating the radial intermediate membrane bead with a third arc length and a third maximum thickness along the radial direction, and at least one fourth zone interpenetrating the radial outer membrane bead with a fourth arc length and a fourth maximum thickness along the radial direction; manufacturing a first layer of the carcass extending along an axial direction Z by depositing a printing material onto a manufacturing platform through the nozzle to form, in any order, (b) producing at least one additional layer according to step (a), wherein a bead of the at least one additional layer overlaps an axially adjacent bead of the preceding layer along the axial direction Z, with remelting of the interface between the preceding layer and the at least one additional layer; a carcass additive manufacturing method comprising, in sequence:

[0023] Essentially, the additive manufacturing method according to the invention makes it possible to obtain the carcass of an airless tire by carrying out a single method of depositing a printing material in the form of a bead ejected from a nozzle, without the need to assemble several parts to form said carcass. Each structural element of the carcass is thus composed of an axial superposition of layers, each layer being composed of a single bead or "monobead", which makes it possible to save time and increase the manufacturing quality of the carcass of an airless tire, while at the same time increasing the mechanical strength of said carcass.

[0024] As a result, the additive manufacturing method of the present invention allows for reduced manufacturing time and improved production quality of the carcass of an airless tire by eliminating the process of assembling the various structural elements required to manufacture the carcass of an airless tire.

[0025] Additionally, the additive manufacturing method according to the present invention does not require high manufacturing costs for the carcass and does not require tools for manufacturing the various structural elements.

[0026] The beads of material deposited by the nozzle of the additive manufacturing machine interpenetrate the connection zones of the various structural elements, thereby improving the mutual adhesion of said various structural elements and thereby improving the mechanical strength properties and / or fatigue limit properties of the carcass.

[0027] Advantageously, the first width, the second width, the third width, the plurality of fourth widths and the plurality of fifth widths are equal to each other, thereby reducing the time required to prepare a carcass model and saving manufacturing time.

[0028] The first width, second width, third width, plurality of fourth widths, and plurality of fifth widths are each at least equal to 0.15 mm and at most equal to 4 mm, and preferably at least equal to 0.4 mm and at most equal to 2 mm, such dimension ranges advantageously allowing for the manufacture of the present subject matter with standard nozzle sizes and existing settings of additive manufacturing machine parameters.

[0029] Also, the first maximum thickness, the second maximum thickness, the third maximum thickness and the fourth maximum thickness are equal to each other, which advantageously reduces the time required to prepare a carcass model and saves manufacturing time.

[0030] Advantageously, the first maximum thickness is at least equal to 2% and at most equal to 20% of the smallest of the first and fourth widths, preferably at least equal to 5% and at most equal to 10% of the smallest of the first and fourth widths.

[0031] Advantageously, the second maximum thickness is at least equal to 2% and at most equal to 20% of the smallest of the second and fourth widths, and preferably at least equal to 5% and at most equal to 10% of the smallest of the second and fourth widths.

[0032] Advantageously, the third maximum thickness is at least equal to 2% and at most equal to 20% of the smallest width of the second and fifth widths, and preferably at least equal to 5% and at most equal to 10% of the smallest width of the second and fifth widths.

[0033] Advantageously, the fourth maximum thickness is at least equal to 2% and at most equal to 20% of the smallest of the third and fifth widths, preferably at least equal to 5% and at most equal to 10% of the smallest of the third and fifth widths.

[0034] The spacing defined above for the first, second, third and fourth thicknesses can maximize the interpenetration of successive layers without adding additional material that can accumulate and cause manufacturing defects or machine shutdowns and degradation.

[0035] Also, the first arc length, the second arc length, the third arc length and the fourth arc length are equal to each other, which advantageously reduces the time required to prepare a carcass model and saves manufacturing time.

[0036] Advantageously, the first arc length is at least equal to three times and at most equal to 100 times the smallest of the first and fourth widths, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the first and fourth widths.

[0037] Advantageously, the second arc length is at least equal to three times and at most equal to 100 times the smallest of the second and fourth widths, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the second and fourth widths.

[0038] Advantageously, the third arc length is at least equal to three times and at most equal to 100 times the smallest of the second and fifth widths, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the second and fifth widths.

[0039] Advantageously, the fourth arc length is at least equal to three times and at most equal to 100 times the smallest of the third and fifth widths, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the third and fifth widths.

[0040] The spacing defined above for the first, second, third and fourth arc lengths allows for achieving sufficient adhesion between the structural elements without increasing the stiffness and mass of the wheel.

[0041] The spokes are preferably uniformly spaced around the circumference.

[0042] The shear elements are also preferably uniformly distributed in the circumferential direction.

[0043] The regular distribution of the spokes and shear elements makes it possible to obtain a carcass with identical mechanical behavior over the entire circumference of the airless tire, in particular under the influence of radial forces.

[0044] The printing material is preferably a polyaryletherketone (PAEK) type thermoplastic, a polyetheretherketone (PEEK) type thermoplastic, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), a glycolated polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET). An example of a polyaryletherketone (PAEK) is the AM200® product from Victrex™. An ​​example of an elastomeric thermoplastic copolyester (TPC-ET) is the Hytrel® product from DuPont™.

[0045] Advantageously, the printing material has a melting temperature at least equal to 180°C and at most equal to 450°C, making it possible to have sufficient thermal integrity when operating in less demanding applications and good malleability during the manufacture of the carcass according to the invention.

[0046] Advantageously, the printed material can be varied between at least two types of beads: radial inner membrane beads, radial intermediate membrane beads, radial outer membrane beads, spoke beads, and shear element beads, thereby allowing the stiffness or flexibility to be specified for each structural element.

[0047] Further subject matter of the invention is a carcass produced using the manufacturing method according to the invention, and an airless tire comprising such a carcass.

[0048] Further objects, features and advantages of the present invention will become more clearly apparent on reading the following description taken in conjunction with the accompanying drawings, which are given purely by way of non-limiting illustration and in which: [Brief explanation of the drawings]

[0049] [Figure 1] 1 is a general perspective view of an airless tire including a carcass produced by an additive manufacturing method according to the present invention; FIG. [Figure 2]FIG. 1 is a general view of an additive manufacturing machine used to implement the method according to the present invention. [Figure 3] FIG. 1 is a general top view of a first layer deposited on a building platform for a carcass of an airless tire. [Figure 4] 1 is a partial axial cross-section of an airless tire manufactured using the method according to the present invention; [Figure 5] 1 is a partial circumferential cross-section of an airless tire carcass produced using a method according to the present invention. [Figure 6] FIG. 10 is a circumferential cross-sectional view of a first interpenetrating zone. [Figure 7] FIG. 10 is a circumferential cross-sectional view of a second interpenetrating zone. [Figure 8] FIG. 10 is a circumferential cross-sectional view of the third and fourth interpenetrating zones. DETAILED DESCRIPTION OF THE INVENTION

[0050] In the following text, for clarity, the horizontal and vertical directions correspond to the natural orientation of Figures 1 to 7. Similarly, the terms "top," "bottom," "lower," "upper," and variations thereof should be understood with reference to the vertical orientation of the figures.

[0051] As can be seen in FIG. 1, the airless tire 1 is configured as follows, from the inside to the outside in the radial direction: a carcass 24 intended to cooperate with a rim or hub 4; a tread 2 intended to cooperate with a carcass 24; Includes.

[0052] The carcass 24 is formed from the inner side to the outer side in the radial direction as follows: a support structure 9 intended to cooperate with the rim or hub 4; - a shear band 3 intended to cooperate with the tread 2; Includes.

[0053] The support structure 9 is radially arranged from the inner side to the outer side as follows: - a radial inner membrane 7 intended to be fixed to the rim or hub 4 by connecting means; - a plurality of radial elements or spokes 8 intended to connect the radial inner membrane 7 with the shear band 3; Includes.

[0054] The means for connecting the radially inner membrane 7 to the rim or hub 4 can be, for example, adhesive means, riveting means, bolting means or hooping means.

[0055] In known embodiments, the shear bands 3 extend radially from the inner to the outer side: - a radial interlayer 10 associated with the support structure 9; a plurality of shear elements 11; a radial outer membrane 5 intended to receive the tread 2 and connected to a radial intermediate membrane 10 by a plurality of shear elements 11; Includes.

[0056] The tread 2 may be fixed to the radially outer membrane 5 of the shear band 3 by fixing means which may be, for example, adhesive means or hooping means.

[0057] The carcass 24 is therefore made up of structural elements 25 including the radially inner membrane 7 , the spokes 8 , the radially intermediate membrane 10 , the shear elements 11 and the radially outer membrane 5 .

[0058] The subject of the present invention is a method for producing a carcass 24 of an airless tire 1 using an additive manufacturing machine 20 .

[0059] 2 is a general view of an example of an additive manufacturing machine 20 employed to carry out a method according to the present invention. The additive manufacturing machine 20 includes a nozzle 12, a manufacturing platform 14, a system 22 for horizontal movement in either circumferential plane XY, and a system 23 for vertical movement along an axial direction Z perpendicular to either circumferential plane XY.

[0060] The horizontal movement system 22 and the vertical movement system 23 allow for the manipulation of the relative movement of the nozzle 12 with respect to the production platform 14 so that the nozzle 12 can deposit molten printing material 21, preferably in the form of continuous beads 13.

[0061] Any other type of additive manufacturing machine involving deposition of a bead 13 of malleable printing material 21 is also suitable, such as, for example, a machine in which relative movement of nozzle 12 with respect to manufacturing platform 14 is achieved by movement of said manufacturing platform 14.

[0062] According to the first step of the method according to the present invention, a first layer of a carcass 24 extending along the axial direction Z is produced by depositing printing material 21 onto the manufacturing platform 14 via the nozzle 12 to form beads (C1, C2, C3, C4, C5) in any order.

[0063] As can be seen in Figures 3 and 5, the nozzle 12 a radially inner membrane bead C1 having a first width R1, intended to produce the radially inner membrane 7 of the carcass 24; a radial interlayer bead C2 having a second width R2, intended to produce the radial interlayer 10 of the carcass 24; a radial outer membrane bead C3 having a third width R3, intended to produce the radial outer membrane 5 of the carcass 24; a plurality of spoke beads C4, each having a fourth width R4, intended to produce a plurality of spokes 8 connecting the radial inner membrane 7 to the radial intermediate membrane 10; a plurality of shear element beads C5, each having a fifth width R5, intended to produce a plurality of shear elements 11 connecting the radial intermediate membrane 10 to the radial outer membrane 5; is deposited.

[0064] As shown in FIG. 6, each of the spoke beads C4 has at least one first zone Z1 interpenetrating with the radial inner bead C1, and the interpenetrating first zone Z1 has a first arc length L1 and a first maximum thickness E1 along the radial direction.

[0065] As shown in FIG. 7, each spoke bead C4 has at least one second zone Z2 interpenetrating with the radial interlayer bead C2, and the interpenetrating second zone Z2 has a second arc length L2 and a second maximum thickness E2 along the radial direction.

[0066] As can be seen in FIG. 8, each of the shear element beads C5 further has at least one third zone Z3 interpenetrating with the radial interlayer bead C2, said interpenetrating third zone Z3 having a third arc length L3 and a third maximum thickness E3 along the radial direction.

[0067] As can be seen in FIG. 8, each of the shear element beads C5 further has at least one fourth zone Z4 interpenetrating with the radial outer membrane bead C3, said fourth interpenetrating zone Z4 having a fourth arc length L4 and a fourth maximum thickness E4 along the radial direction.

[0068] In the method according to the present invention, the nozzle 12 then produces at least one additional layer according to step a, with the beads (C1, C2, C3, C4, C5) of the at least one additional layer overlapping along the axial direction Z with the beads (C1, C2, C3, C4, C5) of the axially adjacent preceding layer, accompanied by remelting of the interface between the preceding layer and the at least one additional layer.

[0069] As can be seen in figure 4, step (a) can be repeated to produce a one-piece carcass 24 of height H along the axial direction Z. The height H of the carcass 24 is clearly adapted to the type of airless tire 1 to be produced, said height H being adjusted in particular to the width of the tread 2 of the airless tire 1.

[0070] By remelting the interface between two adjacent layers, a very strong bond can be obtained between each layer, thus enabling the production of a one-piece carcass 24 having very high mechanical strength.

[0071] By creating interpenetrating zones Z1, Z2, Z3 and Z4 during deposition of the printing material 21, the spokes 8 can be fully attached to the radial inner membrane 7 and the radial intermediate membrane 10, and the shear elements 11 can also be fully attached to the radial intermediate membrane 10 and the radial outer membrane 5.

[0072] This complete adhesion of the structural elements 25 of the carcass 24 to one another results in very high mechanical strength and very good fatigue strength of said carcass 24 under operating stresses.

[0073] During the production of the layers of the carcass 24, it is preferred that the nozzle 12 starts depositing the layer of radially inner bead C1, which is the bead that defines the closure zone, at a starting point different from the starting point of the preceding layer, in order to obtain joining zones located at different horizontal azimuths between two adjacent layers.

[0074] Similarly, the other bead layers C2, C3, each defining a closure zone, are preferably deposited with the starting and ending points of the nozzle 12 different from those of the preceding layer, thereby obtaining joining zones located at different horizontal azimuth angles between the starting and ending points of the beads.

[0075] By obtaining, for each layer of the carcass 24, bond zones located at different horizontal azimuth angles of the beads defining the closure zone, the mechanical strength of the carcass 24 can be increased by preventing the propagation of any cracks in said bond zones.

[0076] In one particular embodiment, as shown in FIG. 5, the first width R1, the second width R2, the third width R3, the plurality of fourth widths R4, and the plurality of fifth widths R5 are equal to each other, and are each equal to at least 0.15 mm and at most 4 mm, preferably at least 4 mm and at most 2 mm.

[0077] In another embodiment, the strength of each structural element 25 can be optimized by adapting the widths R1, R2, R3, R4, and R5 of the structural elements 25. Specifically, each structural element 25 of the carcass 24 has a different shape and stress, so that each width R1, R2, R3, R4, and R5 can be determined as appropriately as possible.

[0078] These thickness variations also allow for a lighter carcass 24, savings in material deposits, and savings in manufacturing time.

[0079] As can be seen in FIG. 5, the first maximum thickness E1, the second maximum thickness E2, the third maximum thickness E3 and the fourth maximum thickness E4 are preferably equal to each other.

[0080] Furthermore, it is preferable that the first arc length L1, the second arc length L2, the third arc length L3, and the fourth arc length L4 are equal to one another.

[0081] Advantageously, the first maximum thickness E1 is equal to at least 2% and at most 20% of the smallest of the first and fourth widths R1, R4, and preferably at least 5% and at most 10% of the smallest of the first and fourth widths R1, R4.

[0082] Advantageously, the second maximum thickness E2 is at least equal to 2% and at most equal to 20% of the smallest of the second and fourth widths R2, R4, and preferably at least equal to 5% and at most equal to 10% of the smallest of the second and fourth widths R2, R4.

[0083] Advantageously, the third maximum thickness E3 is at least equal to 2% and at most equal to 20% of the smallest of the second and fifth widths R2, R5, and preferably at least 5% and at most equal to 10% of the smallest of the second and fifth widths R2, R5.

[0084] Advantageously, the fourth maximum thickness E4 is at least equal to 2% and at most equal to 20% of the smallest of the third and fifth widths R3, R5, and preferably at least 5% and at most equal to 10% of the smallest of the third and fifth widths R3, R5.

[0085] Advantageously, the first arc length L1 is at least equal to three times and at most equal to 100 times the smallest of the first and fourth widths R1, R4, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the first and fourth widths R1, R4.

[0086] Advantageously, the second arc length L2 is at least equal to three times and at most equal to 100 times the smallest of the second and fourth widths R2, R4, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the second and fourth widths R2, R4.

[0087] Advantageously, the third arc length L3 is at least equal to three times and at most equal to 100 times the smallest of the second and fifth widths R2, R5, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the second and fifth widths R2, R5.

[0088] Advantageously, the fourth arc length L4 is at least equal to three times and at most equal to 100 times the smallest of the third and fifth widths R3, R5, and preferably at least equal to 10 times and at most equal to 50 times the smallest of the third and fifth widths R3, R5.

[0089] 5, in the interpenetration zones Z1, Z2, Z3, Z4, the bead of one structural element 25 of the carcass 24 is tangent to the bead of an adjacent structural element 25. This contact results in the structural elements 25 having a shape adapted to the type of stresses to which the carcass 24 is subjected, thereby increasing their mechanical and fatigue strength.

[0090] As known to those skilled in the art, the width and height of the printed bead depend on the geometric dimensions of the exit cross section of the nozzle 12 and the setting parameters of the additive manufacturing machine 20.

[0091] It is advantageous to be able to change the nozzle 12 of the additive manufacturing machine 20 during the production of the layers of the carcass 24 in order to match the width of the deposited beads with the widths R1, R2, R3, R4 and R5 of each bead C1, C2, C3, C4 and C5 of the structural element 25, so that one pass can be performed using the nozzle 12 to produce each layer of said structural element 25.

[0092] The spokes 8 and shear elements 11 are preferably distributed at regular intervals in the circumferential direction.

[0093] Furthermore, in the method according to the invention, it is preferred that the printing material 21 is a thermoplastic of the polyetheretherketone (PEEK) type, for example the product AM200 (registered trademark) of the company Victrex (trademark), an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), a polyaryletherketone (PAEK) type thermoplastic, such as glycolated polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET), for example the product Hytrel (registered trademark) of the company DuPont (trademark).

[0094] Advantageously, the printing material 21 has a melting temperature at least equal to 180°C and at most equal to 450°C.

[0095] Advantageously, the printing material 21 differs between at least two types of beads among the radial inner membrane beads C1, the radial intermediate membrane beads C2, the radial outer membrane beads C3, the spoke beads C4 and the shear element beads C5, so that each structural element 25 has different functional needs in terms of stiffness or flexibility, etc., and therefore a material with the most appropriate technical properties can be selected for the production of each structural element 25.

[0096] The present invention provides the following radially from inner to outer sides: at least two support structures 9, a first radial inner membrane 7 of which is intended to be fixed to the rim or hub 4, and each of the other radial inner membranes 7 serving as an interface between each of a plurality of radial elements or spokes 8; at least two shear bands, the last of which is intended to receive the tread 2 and each of the other radially outer membranes 5 serves as an interface between each of the plurality of shear elements 11; This can be generalized to the case of a carcass 24 of an airless tire 1 including

[0097] Table 1 below shows the characteristics of one embodiment of the carcass 24 intended to manufacture the airless tire 1. [Table 1] TIFF2025540857000002.tif117153

[0098] Further subject matter of the invention is a carcass 24 produced using the manufacturing method according to the invention, and an airless tire 1 comprising such a carcass 24. [Explanation of symbols]

[0099] 3 Shear zone 5 Radial adventitia 7 Radial intima 8 spokes 9 Support structure 10 Radial interlayer 11 Shear elements 14 Manufacturing Platform 24 Carcass 25 Structural Elements C1 Radial intimal bead C2 Radial interlayer bead C3 radial adventitia bead C4 Connected Structure Bead C5 Joint structural bead

Claims

1. A method for additively manufacturing a carcass (24) of an airless tire (1) for a vehicle, comprising: employing an additive manufacturing machine (20) including a manufacturing platform (14) perpendicular to a rotation axis of the carcass (24) having an axial direction Z; and a nozzle (12) movable along the axial direction Z in any circumferential plane XY perpendicular to the axial direction Z; The additive manufacturing method comprises: (a) Beads (C1, C2, C3, C4, C5) such as: a radially inner membrane bead (C1) with a first width (R1) intended to produce the radially inner membrane (7) of said carcass (24); a radial interlayer bead (C2) having a second width (R2) intended to produce the radial interlayer (10) of said carcass (24); a radial outer membrane bead (C3) having a third width (R3) intended to produce the radial outer membrane (5) of said carcass (24); a plurality of spoke beads (C4) each having a fourth width (R4) intended to produce a plurality of spokes (8) connecting said radial inner membrane (7) to said radial intermediate membrane (10), said plurality of spoke beads (C4) having at least one first zone (Z1) interpenetrating said radial inner membrane bead (C1) with a first arc length (L1) and a first maximum thickness (E1) along the radial direction, and each of said plurality of spoke beads (C4) having at least one second zone (Z2) interpenetrating said radial intermediate membrane bead (C2) with a second arc length (L2) and a second maximum thickness (E2) along the radial direction, a plurality of shear element beads (C5) each having a fifth width (R5) intended to produce a plurality of shear elements (11) connecting said radial intermediate membrane (10) to said radial outer membrane (5), said plurality of shear element beads (C5) each having at least one third zone (Z3) interpenetrating said radial intermediate membrane bead (C2) with a third arc length (L3) and a third maximum thickness (E3) along the radial direction, and each of said plurality of shear element beads (C5) having at least one fourth zone (Z4) interpenetrating said radial outer membrane bead (C3) with a fourth arc length (L4) and a fourth maximum thickness (E4) along the radial direction, manufacturing a first layer of the carcass (24) extending along the axial direction Z by depositing a printing material (21) onto the manufacturing platform (14) through the nozzle (12) to form, in any order, (b) producing at least one additional layer according to step (a), wherein the beads (C1, C2, C3, C4, C5) of the at least one additional layer overlap along the axial direction Z with the beads (C1, C2, C3, C4, C5) of the axially adjacent preceding layer, with remelting of the interface between the preceding layer and the at least one additional layer; 1. A method for additively manufacturing a carcass (24), comprising:

2. the first width (R1), the second width (R2), the third width (R3), the plurality of fourth widths (R4), and the plurality of fifth widths (R5) are equal to one another; 10. A method for additively manufacturing a carcass (24) according to claim 1.

3. the first width (R1), the second width (R2), the third width (R3), the plurality of fourth widths (R4) and the plurality of fifth widths (R5) are each at least equal to 0.15 mm and at most equal to 4 mm, preferably at least equal to 0.4 mm and at most equal to 2 mm; A method for additively manufacturing a carcass (24) according to claim 1 or 2.

4. the first maximum thickness (E1), the second maximum thickness (E2), the third maximum thickness (E3), and the fourth maximum thickness (E4) are equal to each other; A method for additively manufacturing a carcass (24) according to any one of claims 1 to 3.

5. the first maximum thickness (E1) is equal to at least 2% and at most 20% of the smallest of the first and fourth widths (R1, R4), preferably at least 5% and at most 10% of the smallest of the first and fourth widths (R1, R4); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 4.

6. the second maximum thickness (E2) is equal to at least 2% and at most 20% of the smallest of the second and fourth widths (R2, R4), preferably at least 5% and at most 10% of the smallest of the second and fourth widths (R2, R4); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 5.

7. the third maximum thickness (E3) is equal to at least 2% and at most 20% of the smallest of the second and fifth widths (R2, R5), preferably at least 5% and at most 10% of the smallest of the second and fifth widths (R2, R5); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 6.

8. the fourth maximum thickness (E4) is equal to at least 2% and at most 20% of the smallest of the third and fifth widths (R3, R5), preferably at least 5% and at most 10% of the smallest of the third and fifth widths (R3, R5); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 7.

9. the first arc length (L1), the second arc length (L2), the third arc length (L3), and the fourth arc length (L4) are equal to each other; A method for additively manufacturing a carcass (24) according to any one of claims 1 to 8.

10. the first arc length (L1) is at least equal to three times and at most equal to 100 times the smallest width of the first and fourth widths (R1, R4), preferably at least equal to 10 times and at most equal to 50 times the smallest width of the first and fourth widths (R1, R4); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 9.

11. the second arc length (L2) is at least equal to three times and at most equal to 100 times the smallest width of the second and fourth widths (R2, R4), preferably at least equal to 10 times and at most equal to 50 times the smallest width of the second and fourth widths (R2, R4); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 10.

12. the third arc length (L3) is at least equal to three times and at most equal to 100 times the smallest width of the second and fifth widths (R2, R5), preferably at least equal to 10 times and at most equal to 50 times the smallest width of the second and fifth widths (R2, R5); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 11.

13. the fourth arc length (L4) is at least equal to three times and at most equal to 100 times the smallest width of the third and fifth widths (R3, R5), preferably at least equal to 10 times and at most equal to 50 times the smallest width of the third and fifth widths (R3, R5); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 12.

14. The spokes (8) are distributed at regular intervals in the circumferential direction. A method for additively manufacturing a carcass (24) according to any one of claims 1 to 13.

15. The shearing elements (11) are distributed at regular intervals in the circumferential direction. A method for additively manufacturing a carcass (24) according to any one of claims 1 to 14.

16. the printing material (21) is a thermoplastic of the polyaryletherketone (PAEK) type, a thermoplastic of the polyetheretherketone (PEEK) type, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), a glycolized polyester (PETG) or an elastomeric thermoplastic copolyester (TPC-ET); A method for additively manufacturing a carcass (24) according to any one of claims 1 to 15.

17. said printing material (21) having a melting temperature at least equal to 180°C and at most equal to 450°C; 17. A method for additively manufacturing a carcass (24) according to claim 16.

18. the printing material (21) is different between at least two types of beads among the radial inner membrane beads (C1), the radial intermediate membrane beads (C2), the radial outer membrane beads (C3), the spoke beads (C4) and the shear element beads (C5); 17. A method for additively manufacturing a carcass (24) according to claim 16.

19. A carcass (24) for an airless tire (1) produced by carrying out the manufacturing method according to one of claims 1 to 18.

20. An airless tire (1) comprising a carcass (24) according to claim 19.

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