Additive manufacturing method of cartridge of air-free tire for vehicle

Abstract

There is provided an additive manufacturing method intended for producing a carcass (24) of an airless tire (1), the additive manufacturing method employing an additive manufacturing machine (20) producing a plurality of layers of structural elements (25) of the carcass (24) in any XY plane perpendicular to the axis of rotation of the carcass (24) by depositing strips of fusible printing material, the belt portion of each structural element (25) is continuous and has a portion that is inserted into the belt portion of each adjacent structural element (25) in any XY plane.

Description

Technical Field

[0001] The present invention belongs to the field of methods for manufacturing non-pneumatic tires intended to be assembled to a vehicle.

[0002] The present invention more particularly relates to an additive manufacturing method for manufacturing a non-pneumatic tire by means of a 3D printer by depositing a plastic printable material in successive layers by means of a nozzle. Background Art

[0003] Printers generally include a chamber which forms a housing delimited by walls, inside which there is a platform intended to support the part being printed and a nozzle for supplying the material for manufacturing the part. In order to be able to produce the shape of the part, a drive system is provided which includes a lifter for vertically moving the platform or the nozzle and translational stages which cross each other and which are intended to horizontally manoeuvre the platform or the nozzle (the nozzle being intended to convey the material for manufacturing the part).

[0004] Document US 6 722 872 particularly describes such a printer.

[0005] A non-pneumatic tire or more generally a tire without inflation gas is a tire which supports the load by means of structural elements which form the carcass and which has performance comparable to that of a conventional tire subjected to an internal gas (generally air) pressure. A non-pneumatic tire mounted on a hub or a rim is sometimes referred to as a "non-inflatable elastic wheel".

[0006] Hereinafter, the circumferential or longitudinal direction denotes the direction of rotation of the tire, the axial or transverse direction denotes the direction parallel to the axis of rotation of the tire, and the radial direction denotes the direction perpendicular to the axis of rotation of the tire.

[0007] A non-pneumatic tire generally includes, in the radial direction from the inside to the outside:

[0008] - a carcass which is formed by structural elements and which is intended to cooperate with a rim or a hub,

[0009] - a tread which is intended to cooperate with the carcass and which transmits the running forces to the carcass, so as to be worn and to ensure the grip of the tire on the ground.

[0010] The carcass includes, in the radial direction from the inside to the outside:

[0011] - a support structure which is intended to structurally support at least part of the load,

[0012] - a shear band which is intended to transmit the running forces to the support structure by shear and which at least partly contributes to supporting the load.

[0013] The support structure generally includes, in the radial direction from the inside to the outside:

[0014] - A radial inner membrane, which is intended to be fixed to the rim or hub by a connecting means,

[0015] - A coupling structure, which is intended to be fixed to the radial inner membrane and the shear band by a connecting means. However, the support structure generally does not define a sealed inner cavity intended to accommodate pressurized gas as in a conventional tire. Therefore, a non-pneumatic tire does not need to have a sealed connection to the rim or hub.

[0016] In known embodiments, the shear band includes, from the inside to the outside in the radial direction:

[0017] - A radial intermediate membrane, which is in contact with the coupling structure,

[0018] - A joining structure,

[0019] - A radial outer membrane, which is intended to receive the tread and is connected to the radial intermediate membrane by the joining structure.

[0020] Typically, the tread is fixed to the radial outer membrane of the shear band by a fixing means, which can be, for example, an adhesive or a banding means.

[0021] Thus, the carcass has a plurality of elements called structural elements, which can, for example, include a radial inner membrane, a plurality of spokes, a radial intermediate membrane, a plurality of shear elements, and a radial outer membrane.

[0022] Methods for manufacturing the carcass of a non-pneumatic tire well-known to those skilled in the art include: first, manufacturing various structural elements independently, and second, assembling the structural elements according to an assembly and precise positioning method. Different methods such as adhesive bonding, riveting, bolting, crimping, or ultrasonic welding can be used to hold the various structural elements in place.

[0023] For example, such methods for assembling non-pneumatic tires are described in documents US20220194129A1, WO2008 / 136099A1, US9908369B2.

[0024] Although such methods can manufacture non-pneumatic tires, their disadvantages are particularly related to the weak adhesion between the various elements constituting such a carcass.

[0025] In addition, the manufacturing quality of such carcasses intended for the production of non-pneumatic tires is not always satisfactory. There are variations in the geometric dimensions related to the manufacturing of each structural element plus variations in the positioning in the assembly method, which potentially have an adverse impact on the overall quality and performance aspects of the non-pneumatic tire.

[0026] In addition, the assembly method is quite complex and requires a large number of interventions to position the various structural elements, which results in high manufacturing costs.

[0027] Other methods for manufacturing a non-pneumatic tire carcass using molding methods for producing different structural elements are also known to those skilled in the art. These methods are described, for example, in document JP 2022034665A.

[0028] These methods for manufacturing structural elements by molding require the manufacture of expensive tools such as molds and cannot generate the complex geometries that are sometimes necessary for manufacturing the structural elements of a non-pneumatic tire carcass. Summary of the Invention

[0029] Accordingly, the present invention aims to overcome the above disadvantages and provide a manufacturing method for simply producing a non-pneumatic tire carcass at low cost, which can use a wide range of materials while ensuring excellent reproducibility of the manufacturing and ideal adhesion between various structural elements of the non-pneumatic tire carcass.

[0030] The subject of the present invention is an additive manufacturing method for a non-pneumatic tire carcass for a vehicle, which uses an additive manufacturing machine including a manufacturing platform and a nozzle, the manufacturing platform being perpendicular to the axis of rotation of the carcass having an axial direction Z, the nozzle being capable of moving along the axial direction Z and being capable of moving in any circumferential plane XY perpendicular to the axial direction Z, the additive manufacturing method including the following successive steps:

[0031] (a) Manufacturing a first layer of the carcass extending along the axial direction Z by depositing a printing material via the nozzle on the manufacturing platform, thereby forming, in any order, the following cordons:

[0032] - A radial inner membrane cordon, which is intended for manufacturing the radial inner membrane of the carcass and has a first width,

[0033] - A radial intermediate membrane cordon, which is intended for manufacturing the radial intermediate membrane of the carcass and has a second width,

[0034] - A radial outer membrane cordon, which is intended for manufacturing the radial outer membrane of the carcass and has a third width,

[0035] - A connection structure cordon, which is intended for manufacturing a connection structure that connects the radial inner membrane to the radial intermediate membrane via a plurality of connection portions, the connection structure cordon having a fourth width, the connection structure cordon having a plurality of first regions that penetrate into the radial inner membrane cordon, each of the first penetration regions having a first arc length and a first maximum thickness along the radial direction, the connection structure cordon further having a plurality of second regions that penetrate into the radial intermediate membrane cordon, each of the second penetration regions having a second arc length and a second maximum thickness along the radial direction,

[0036] - A strip of the joining structure, which is intended for manufacturing a joining structure that connects a radially intermediate film to a radially outer film via a plurality of joining portions. The strip of the joining structure has a fifth width. The strip of the joining structure has a plurality of third regions that are interposed into the strip of the radially intermediate film. Each of the interposed third regions has a third arc length and a third maximum thickness along the radial direction. The strip of the joining structure also has a plurality of fourth regions that are interposed into the strip of the radially outer film. Each of the fourth interposed regions has a fourth arc length and a fourth maximum thickness along the radial direction.

[0037] (b) Generate at least one additional layer according to step (a), and the strip of the at least one additional layer is stacked axially with the strip of the axially adjacent previous layer, wherein the interface between the previous layer and the at least one additional layer is remelted.

[0038] Substantially, the additive manufacturing method according to the present invention enables the carcass of a non-pneumatic tire to be obtained by implementing a single method of depositing the printing material exiting the nozzle in the form of a strip, without the need to assemble a variety of components to form the carcass. Therefore, each structural element of the carcass is composed of axially stacked layers, and each layer is composed of a single strip or a "single strip", and the "single strip" can save time and improve the manufacturing quality of the non-pneumatic tire carcass, while improving the mechanical strength of the carcass.

[0039] Therefore, the additive manufacturing method of the present invention enables the process of assembling various structural elements required for manufacturing the non-pneumatic tire carcass to be omitted, thereby saving manufacturing time and improving the production quality of the non-pneumatic tire carcass.

[0040] In addition, the additive manufacturing method does not require tools to manufacture various structural elements, thereby reducing the manufacturing cost of the carcass.

[0041] Since the strips of material deposited through the nozzle of the additive manufacturing machine interpenetrate each other in the connection regions of various structural elements, the mutual adhesion of the various structural elements is improved, so that the carcass can obtain better mechanical strength performance and / or fatigue limit performance.

[0042] Advantageously, the first width, the second width, the third width, the fourth width, and the fifth width are equal to each other, so that the time for preparing the carcass model can be reduced and the production time can be saved.

[0043] Advantageously, the first width, the second width, the third width, the fourth width, and the fifth width are respectively 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. Such a size range enables the subject article to be manufactured with standard nozzle sizes and existing parameter settings of the additive manufacturing machine.

[0044] Advantageously, the first maximum thickness, the second maximum width, the third maximum thickness and the fourth maximum thickness are equal to each other, so that the time for preparing the carcass model can be reduced and the production time can be saved.

[0045] Advantageously, the first maximum thickness is at least equal to 2% of the minimum width of the first width and the fourth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width and the fourth width and at most equal to 10% of the minimum width.

[0046] Advantageously again, the second maximum thickness is at least equal to 2% of the minimum width of the second width and the fourth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width and the fourth width and at most equal to 10% of the minimum width.

[0047] Advantageously further, the third maximum thickness is at least equal to 2% of the minimum width of the second width and the fifth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width and the fifth width and at most equal to 10% of the minimum width.

[0048] Advantageously, the fourth maximum thickness is at least equal to 2% of the minimum width of the third width and the fifth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width and the fifth width and at most equal to 10% of the minimum width.

[0049] The intervals defined by the first thickness, the second thickness, the third thickness and the fourth thickness above can maximize the interpenetration of the continuous layers without adding additional materials that may accumulate and cause manufacturing defects or even machine downtime and deterioration.

[0050] Advantageously, the first arc length is at least equal to 3 times the minimum width of the first width and the fourth width and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the first width and the fourth width and at most equal to 60 times the minimum width.

[0051] Advantageously again, the second arc length is at least equal to 3 times the minimum width of the second width and the fourth width and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the second width and the fourth width and at most equal to 60 times the minimum width.

[0052] Advantageously further, the third arc length is at least equal to 3 times the minimum width of the second width and the fifth width and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the second width and the fifth width and at most equal to 60 times the minimum width.

[0053] Advantageously, the fourth arc length is at least equal to three times the smallest width of the third width and the fifth width and at most equal to 150 times the smallest width, preferably at least equal to ten times the smallest width of the third width and the fifth width and at most equal to 60 times the smallest width.

[0054] The intervals defined by the first arc length, the second arc length, the third arc length, and the fourth arc length above enable sufficient adhesion between structural elements without increasing the stiffness and mass of the wheel.

[0055] Preferably, the plurality of coupling portions include at least two types of coupling portions having different patterns, and each of the coupling portions having different patterns is distributed at a constant pitch in the circumferential direction.

[0056] Again preferably, the plurality of joining portions include at least two types of joining portions having different patterns, and each of the joining portions having different patterns is distributed at a constant pitch in the circumferential direction.

[0057] The distribution of at least two types of coupling portions having different patterns and at least two types of joining portions having different patterns at a constant pitch enables the obtained carcass to have the same mechanical operation (especially under the applied radial force) throughout the circumference of the non-pneumatic tire.

[0058] Preferably, the printing material 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), an ethanolized polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET). Examples of polyaryletherketone (PAEK) are products from Victrex TM product AM Examples of elastomeric thermoplastic copolyester (TPC-ET) are products from DuPont TM product

[0059] Advantageously, the printing material has a melting temperature of at least 180 °C and at most 450 °C, so that sufficient thermal integrity during operation can be achieved for less demanding applications and good plasticity can be achieved during the manufacture of the carcass according to the present invention.

[0060] Advantageously, the printing materials of at least two types of belt portions among the radial inner membrane belt portion, the radial intermediate membrane belt portion, the radial outer membrane belt portion, the coupling structure belt portion, and the joining structure belt portion are different, so that stiffness or flexibility can be specified for each structural element.

[0061] Other subjects of the present invention are a carcass produced by using the manufacturing method according to the present invention, and a non-pneumatic tire including such a carcass. Description of the Drawings

[0062] Other objects, features, and advantages of the present invention will become more apparent by reading the following description in detail and referring to the accompanying drawings, which are provided by way of non-limiting illustration only, in which:

[0063] - Figure 1 : An overall perspective view of a non-pneumatic tire including a carcass produced by an additive manufacturing method according to the present invention.

[0064] - Figure 2 : An overall view of an additive manufacturing machine for implementing the method according to the present invention.

[0065] - Figure 3 : An overall top view of the first layer deposited on the manufacturing platform of the non-pneumatic tire carcass.

[0066] - Figure 4 : A partial view of an axial section of a non-pneumatic tire produced using the method according to the present invention.

[0067] - Figure 5 : A partial view of a circumferential section of a non-pneumatic tire carcass produced using the method according to the present invention.

[0068] - Figure 6 : A view of a circumferential section of the first interpenetrating region.

[0069] - Figure 7 : A view of a circumferential section of the second interpenetrating region.

[0070] - Figure 8 : A view of a circumferential section of the third and fourth interpenetrating regions. Detailed Description of the Invention

[0071] Hereinafter, for clarity, the horizontal and vertical directions correspond to the Figures 1 to 7 natural orientation. Similarly, the terms "top", "bottom", "lower", "upper" and their variants should be understood with reference to the vertical direction in the figures.

[0072] As Figure 1 can be seen, the non-pneumatic tire 1 includes, in the radial direction from the inside to the outside:

[0073] - A carcass 24, which is intended to cooperate with a rim or a hub 4,

[0074] - A tread 2, which is intended to cooperate with the carcass 24.

[0075] The carcass 24 includes, in the radial direction from the inside to the outside:

[0076] - A support structure 9, which is intended to cooperate with a rim or a hub 4,

[0077] - The shear band 3, which is intended to cooperate with the tread 2.

[0078] The support structure 9 includes, in the radial direction from the inside to the outside:

[0079] - The radial inner membrane 7, which is intended to be fixed to the rim or hub 4 by a connection means,

[0080] - The coupling structure 28, which is intended to connect the radial inner membrane 7 and the shear band 3.

[0081] The means for connecting the radial inner membrane 7 to the rim or hub 4 can be, for example, bonding, riveting, bolting or banding.

[0082] In a known embodiment, the shear band 3 includes, in the radial direction from the inside to the outside:

[0083] - The radial intermediate membrane 10, which is in contact with the coupling structure,

[0084] - The joining structure 29,

[0085] - The radial outer membrane 5, which is intended to receive the tread 2 and is connected to the radial intermediate membrane 10 by the joining structure 29.

[0086] The tread 2 can be fixed to the radial outer membrane 5 of the shear band 3 by a fixing means, which can be, for example, bonding or banding.

[0087] Thus, the carcass 24 is composed of structural elements 25, which include the radial inner membrane 7, the coupling structure 28, the radial intermediate membrane 10, the joining structure 29 and the radial outer membrane 5.

[0088] The subject of the present invention is a method for producing the carcass 24 of a non-pneumatic tire 1 using an additive manufacturing machine 20.

[0089] Figure 2 Figure 37 is an overall view of an embodiment of an additive manufacturing machine 20 for performing the 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 any circumferential plane XY and a system 23 for vertical movement along an axial direction Z perpendicular to any circumferential plane XY.

[0090] The horizontal movement system 22 and the vertical movement system 23 enable relative movement of the nozzle 12 with respect to the manufacturing platform 14 so that the nozzle 12 can deposit the molten printing material 21 in the form of a preferably continuous strip 13.

[0091] Any other type of additive manufacturing machine capable of depositing a strip 13 of the plasticizable printing material 21 is suitable, for example, a machine that achieves relative movement of the nozzle 12 with respect to the manufacturing platform 14 by moving the manufacturing platform 14.

[0092] According to the first step of the method of the present invention, the first layer of the carcass 24 extending along the axial direction Z is generated by depositing the printing material 21 on the manufacturing platform 14 via the nozzle 12, thereby forming the belt portions C1, C2, C3, C4, C5 in any order.

[0093] As Figure 3 and Figure 5 can be seen, the nozzle 12 will deposit:

[0094] - a radial inner membrane belt portion C1, which is intended for manufacturing the radial inner membrane 7 of the carcass 24 and has a first width R1,

[0095] - a radial intermediate membrane belt portion C2, which is intended for manufacturing the radial intermediate membrane 10 of the carcass 24 and has a second width R2,

[0096] - a radial outer membrane belt portion C3, which is intended for manufacturing the radial outer membrane 5 of the carcass 24 and has a third width R3,

[0097] - a connection structure belt portion C4, which is intended for manufacturing a connection structure 28 that connects the radial inner membrane 7 to the radial intermediate membrane 10 via a plurality of connection portions 26, and the connection structure belt portion C4 has a fourth width R4,

[0098] - a joint structure belt portion C5, which is intended for manufacturing a joint structure 29 that connects the radial intermediate membrane 10 to the radial outer membrane 5 via a plurality of joint portions 27, and the joint structure belt portion C5 has a fifth width R5.

[0099] As Figure 6 shown, the connection structure belt portion C4 has a plurality of first regions Z1 that penetrate into the radial inner membrane belt portion C1, and each of the penetrating first regions Z1 has a first arc length L1 and a first maximum thickness E1 along the radial direction.

[0100] As Figure 7 shown, the structure belt portion C4 also has a plurality of second regions Z2 that penetrate into the radial intermediate membrane belt portion C2, and each of the penetrating second regions Z2 has a second arc length L2 and a second maximum thickness E2 along the radial direction.

[0101] As Figure 8 can be seen, the joint structure belt portion C5 has a plurality of third regions Z3 that penetrate into the radial intermediate membrane belt portion C2, and each of the penetrating third regions Z3 has a third arc length L3 and a third maximum thickness E3 along the radial direction.

[0102] Again, as Figure 8As shown, the joint structure belt portion C5 also has a plurality of fourth regions Z4 that penetrate into the radially outer membrane belt portion C3, and each of the penetrating fourth regions Z4 has a fourth arc length L4 and a fourth maximum thickness E4 along the radial direction.

[0103] In the method according to the present invention, the nozzle 12 then produces at least one additional layer according to step (a), and the belt portions (C1, C2, C3, C4, C5) of the at least one additional layer are stacked along the axial direction Z with the belt portions (C1, C2, C3, C4, C5) of the axially adjacent previous layer, wherein the interface between the previous layer and the at least one additional layer is remelted.

[0104] As Figure 4 can be seen, repeating step (a) makes it possible to produce a one-piece carcass 24 having a height H along the axial direction Z. The height H of the carcass 24 obviously has to be adapted to the type of the non-pneumatic tire 1 to be produced. In particular, the height H has to be adjusted to the width of the tread 2 of the non-pneumatic tire 1.

[0105] The remelting of the interface between two adjacent layers makes it possible to obtain a very firm bond between the respective layers, so that it is possible to manufacture a one-piece carcass 24 with very high mechanical strength.

[0106] Generating the interpenetrating regions Z1, Z2, Z3 and Z4 during the deposition of the printing material 21 makes it possible to ideally bond the coupling structure 28 to the radially inner membrane 7 and the radially intermediate membrane 10, and also to ideally bond the joint structure 29 to the radially intermediate membrane 10 and the radially outer membrane 5.

[0107] This ideal bonding between the structural elements 25 of the carcass 24 enables the carcass 24 to obtain very high mechanical strength and very good fatigue strength under working stresses.

[0108] Preferably, during the process of manufacturing the layers of the carcass 24, the nozzle 12 starts depositing the layer of the radially inner membrane belt portion C1 (which is a belt portion defining a closed region) at a starting point different from that of the previous layer, so as to obtain a joint region at a different horizontal azimuth angle between two adjacent layers.

[0109] In the same way, the layers of the other belt portions C2, C3 (each of which also defines a closed region) are also preferably deposited with a starting point and an end point different from those of the previous layer by the nozzle 12, so that it is also possible to obtain a joint region at a different horizontal azimuth angle between the start and the end of the belt portion.

[0110] Obtaining joint regions at different horizontal azimuth angles of the belt portions (which define closed regions) for each layer of the carcass 24 makes it possible to improve the mechanical strength of the carcass 24 by preventing crack propagation that may occur in the joint regions.

[0111] In a particular embodiment, as Figure 5 shown, the first width R1, the second width R2, the third width R3, the fourth width R4, and the fifth width R5 are equal to each other, at least equal to 0.15 mm and at most equal to 4 mm respectively, preferably at least equal to 4 mm and at most equal to 2 mm.

[0112] In another embodiment, the strength of each structural element 25 can be optimized by the following means: adjusting the widths R1, R2, R3, R4, and R5 of the structural element 25. Specifically, each structural element 25 of the carcass 24 has different shapes and stresses, and the respective widths R1, R2, R3, R4, and R5 can be determined as appropriately as possible.

[0113] These thickness differences also make it possible to reduce the weight of the carcass 24, save the amount of deposited material, and save manufacturing time.

[0114] Preferably, as Figure 5 visible, 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.

[0115] Advantageously, the first maximum thickness E1 is at least equal to 2% of the minimum width of the first width R1 and the fourth width R4 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width R1 and the fourth width R4 and at most equal to 10% of the minimum width.

[0116] Again advantageously, the second maximum thickness E2 is at least equal to 2% of the minimum width of the second width R2 and the fourth width R4 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width R2 and the fourth width R4 and at most equal to 10% of the minimum width.

[0117] Also advantageously, the third maximum thickness E3 is at least equal to 2% of the minimum width of the second width R2 and the fifth width R5 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width R2 and the fifth width R5 and at most equal to 10% of the minimum width.

[0118] Again advantageously, the fourth maximum thickness E4 is at least equal to 2% of the minimum width of the third width R3 and the fifth width R5 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width R3 and the fifth width R5 and at most equal to 10% of the minimum width.

[0119] Advantageously, the first arc length L1 is at least equal to three times the minimum width of the first width R1 and the fourth width R4 and at most equal to 150 times the minimum width, preferably at least equal to ten times the minimum width of the first width R1 and the fourth width R4 and at most equal to 60 times the minimum width.

[0120] Also advantageously, the second arc length L2 is at least equal to three times the minimum width of the second width R2 and the fourth width R4 and at most equal to 150 times the minimum width, preferably at least equal to ten times the minimum width of the second width R2 and the fourth width R4 and at most equal to 60 times the minimum width.

[0121] Again advantageously, the third arc length L3 is at least equal to three times the minimum width of the second width R2 and the fifth width R5 and at most equal to 150 times the minimum width, preferably at least equal to ten times the minimum width of the second width R2 and the fifth width R5 and at most equal to 60 times the minimum width.

[0122] Also advantageously, the fourth arc length L4 is at least equal to three times the minimum width of the third width R3 and the fifth width R5 and at most equal to 150 times the minimum width, preferably at least equal to ten times the minimum width of the third width R3 and the fifth width R5 and at most equal to 60 times the minimum width.

[0123] As Figure 5 visible, in the interpenetration regions Z1, Z2, Z3, Z4, the strip portion of a structural element 25 of the carcass 24 is tangent to the strip portion of an adjacent structural element 25. This tangency enables the structural element 25 to have a geometry suitable for the type of stress to which the carcass 24 is subjected, thereby improving the mechanical strength and fatigue strength of the structural element 25.

[0124] As is well known to those skilled in the art, the width and height of the printed strip portion depend on the geometric dimensions of the outlet cross-section of the nozzle 12 and the setting parameters of the additive manufacturing machine 20.

[0125] Advantageously, the nozzle 12 of the additive manufacturing machine 20 can be changed during the manufacture of the layer of the carcass 24 so that the width of the deposited strip portion is consistent with the respective widths R1, R2, R3, R4, and R5 of the strip portions C1, C2, C3, C4, and C5 of the structural element 25, thereby enabling each layer of the structural element 25 to be produced with a single pass of the nozzle 12.

[0126] Preferably, the plurality of connecting portions 26 includes at least two connecting portions 26 having different patterns, and the connecting portions 26 having different patterns are distributed at a constant pitch in the circumferential direction.

[0127] Again preferably, the plurality of joining portions 27 include at least two types of joining portions 27 having different patterns, and the joining portions 27 having different patterns are distributed at a constant pitch in the circumferential direction.

[0128] Still in the method according to the invention, the printing material 21 is preferably a thermoplastic of the polyaryletherketone (PAEK) type (e.g. a product from Victrex TM products ), a thermoplastic of the polyetheretherketone (PEEK) type, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), an ethanolized polyester (PETG) or an elastomeric thermoplastic copolyester (TPC-ET) (e.g. a product from DuPont TM products ).

[0129] Advantageously, the printing material 21 has a melting temperature of at least equal to 180 °C and at most equal to 450 °C.

[0130] Advantageously, the printing materials 21 of at least two types of belt portions among the radial inner belt portion C1, the radial intermediate belt portion C2, the radial outer belt portion C3, the connecting structure belt portion C4 and the joining structure belt portion C5 are different. Thus, since each structural element 25 has different functional requirements (e.g. in terms of stiffness or flexibility), materials with the most suitable technical characteristics can be selected to produce each structural element 25.

[0131] The continuity of the connecting structure belt portion C4 and the joining structure belt portion C5 enables minimizing the stop phase and the start phase during the deposition of the belt portions (C4, C5), thus saving time and resulting in better manufacturing quality of the airless tire carcass.

[0132] The present invention can be summarized as a carcass 24 for an airless tire 1, the carcass 24 comprising, in the radial direction from the inside to the outside:

[0133] - at least two support structures 9, the first radial inner membrane 7 of the first support structure 9 being intended to be fixed to the rim or hub 4, and the other radial inner membranes 7 each serving as an interface between various connecting structures 28,

[0134] - and / or at least two shear bands 3, the last radial outer membrane 5 being intended to receive the tread 2, and the other radial outer membranes 5 each serving as an interface between various joining structures 29.

[0135] Table 1 below shows the characteristics of an embodiment intended for manufacturing the carcass 24 of the airless tire 1:

[0136] [Table 1]

[0137]

[0138]

[0139] Other subjects of the present invention are the carcass 24 produced by the manufacturing method according to the present invention, and the non-pneumatic tire 1 including such a carcass 24.

Claims

1. An additive manufacturing method for a carcass (24) of a non-pneumatic tire (1) for a vehicle, which uses an additive manufacturing machine (20) including a manufacturing platform (14) and a nozzle (12), the manufacturing platform (14) being perpendicular to a rotation axis having an axial direction Z of the carcass (24), the nozzle (12) being capable of moving along the axial direction Z and capable of moving in any circumferential plane XY perpendicular to the axial direction Z, The additive manufacturing method includes the following consecutive steps: (a) Manufacturing a first layer of the carcass (24) extending along the axial direction Z by depositing a printing material (21) via the nozzle (12) on the manufacturing platform (14), thereby forming, in any order, the following belt portions (C1, C2, C3, C4, C5): - A radial inner membrane belt portion (C1), which is intended for manufacturing a radial inner membrane (7) of the carcass (24) and has a first width (R1), - A radial intermediate membrane belt portion (C2), which is intended for manufacturing a radial intermediate membrane (10) of the carcass (24) and has a second width (R2), - A radial outer membrane belt portion (C3), which is intended for manufacturing a radial outer membrane (5) of the carcass (24) and has a third width (R3), - A connection structure belt portion (C4), which is intended for manufacturing a connection structure (28) that connects the radial inner membrane (7) to the radial intermediate membrane (10) via a plurality of connection portions (26), the connection structure belt portion having a fourth width (R4), the connection structure belt portion (C4) having a plurality of first regions (Z1) that penetrate into the radial inner membrane belt portion (C1), each of the first penetration regions (Z1) having a first arc length (L1) and a first maximum thickness (E1) along the radial direction, the connection structure belt portion (C4) further having a plurality of second regions (Z2) that penetrate into the radial intermediate membrane belt portion (C2), each of the second penetration regions (Z2) having a second arc length (L2) and a second maximum thickness (E2) along the radial direction, - A joining structure belt portion (C5), which is intended for manufacturing a joining structure (27) that connects the radial intermediate membrane (10) to the radial outer membrane (5) via a plurality of joining portions, the joining structure belt portion (C5) having a fifth width (R5), the joining structure belt portion (C5) having a plurality of third regions (Z3) that penetrate into the radial intermediate membrane belt portion (C2), each of the penetration third regions (Z3) having a third arc length (L3) and a third maximum thickness (E3) along the radial direction, the joining structure belt portion (C5) further having a plurality of fourth regions (Z4) that penetrate into the radial outer membrane belt portion (C3), each of the fourth penetration regions (Z4) having a fourth arc length (L4) and a fourth maximum thickness (E4) along the radial direction, (b) Generate at least one additional layer according to step (a), wherein the bands (C1, C2, C3, C4, C5) of the at least one additional layer are stacked along the axial direction with the bands (C1, C2, C3, C4, C5) of the axially adjacent previous layer, and the interface between the previous layer and the at least one additional layer is remelted.

2. The additive manufacturing method of the carcass (24) according to claim 1, wherein, The first width (R1), the second width (R2), the third width (R3), the fourth width (R4) and the fifth width (R5) are equal to each other.

3. The additive manufacturing method of the carcass (24) according to any one of claims 1 and 2, wherein, The first width (R1), the second width (R2), the third width (R3), the fourth width (R4) and the fifth width (R5) are respectively 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.

4. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 3, wherein, 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.

5. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 4, wherein, The first maximum thickness (E1) is at least equal to 2% of the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 10% of the minimum width.

6. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 5, wherein, The second maximum thickness (E2) is at least equal to 2% of the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 10% of the minimum width.

7. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 6, wherein, The third maximum thickness (E3) is at least equal to 2% of the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 10% of the minimum width.

8. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 7, wherein, The fourth maximum thickness (E4) is at least equal to 2% of the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 10% of the minimum width.

9. An additive manufacturing method of the carcass (24) according to any one of claims 1 to 8, wherein, The first arc length (L1) is at least equal to 3 times the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 60 times the minimum width.

10. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 9, wherein, The second arc length (L2) is at least equal to 3 times the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 60 times the minimum width.

11. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 10, wherein, The third arc length (L3) is at least equal to 3 times the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 60 times the minimum width.

12. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 11, wherein, The fourth arc length (L4) is at least equal to 3 times the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 150 times the minimum width, preferably at least equal to 10 times the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 60 times the minimum width.

13. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 12, wherein, The plurality of connecting portions (26) includes at least two types of connecting portions (26) having different patterns, and each of the connecting portions (26) having different patterns is distributed at a constant pitch in the circumferential direction.

14. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 13, wherein, The plurality of engaging portions (27) includes at least two types of engaging portions (27) having different patterns, and each of the engaging portions (27) having different patterns is distributed at a constant pitch in the circumferential direction.

15. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 14, wherein, The printing material (21) is a polyaryletherketone (PAEK) type thermoplastic, a polyetheretherketone (PEEK) type thermoplastic, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), an ethanolized polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET).

16. The additive manufacturing method of the carcass (24) according to claim 15, wherein, The printing material (21) has a melting temperature of at least 180°C and at most 450°C.

17. The additive manufacturing method of the carcass (24) according to claim 15, wherein, The printing materials (21) of at least two types of belt portions among the radial inner belt portion (C1), the radial intermediate belt portion (C2), the radial outer belt portion (C3), the connecting structure belt portion (C4), and the engaging structure belt portion (C5) are different.

18. The carcass (24) of the non-pneumatic tire (1), which is produced by implementing the manufacturing method according to any one of claims 1 to 17.

19. A non-pneumatic tire (1), which includes the carcass (24) according to claim 18.

Images