Device and method for additive manufacturing of a tire tread

Abstract

Device (10) for additive manufacturing all or part of a tread (6) of a tire (4), configured to deposit an extruded material forming the tread (6) onto a tire (4). The device (10) comprises a drive element for rotating the tire (4) about a horizontal axis of rotation (XX), and at least one material deposition ramp (20, 30) intended to be disposed above the tread of the tire (4) and comprising a plurality of material deposition nozzles, each provided with at least one distribution orifice, each capable of being closed by a closing means (28a), the device (10) comprising at least one actuation system configured to move the material deposition ramp (20, 30) in translation relative to the tire (4) in a vertical direction (Z) and / or a longitudinal direction (X) parallel to the axis of rotation (XX) along the width of the tire (4).Figure for the abridged version: Fig 1.

Description

Title of the invention: Device and method for additive manufacturing of a tire tread

[0001] The present invention relates to the field of manufacturing a tire tread.

[0002] Conventional wheels are known which comprise a rim on which a tyre is mounted comprising a tread and two sidewalls. This type of wheel comprises an inner tube inflated to the recommended nominal inflation pressure.

[0003] Another type of tubeless wheel is also known, known as "tubeless" in Anglo-Saxon terms, comprising an insert made up of several layers of expanded plastic to replace the inner tube.

[0004] Integral wheels are also known comprising a radial load-bearing structure, generally made of glass-fibre reinforced plastic material, around which is fixed a solid bandage comprising a tread and two lateral flanks. The solid bandage is not subjected to internal pressure.

[0005] Such an integral wheel has the advantage of being flexible in the event of impacts, puncture-proof and durable due to the materials it is made of. Furthermore, once worn, it is known to remove the tread and recycle it. Thus, such an integral wheel also makes it possible to meet environmental constraints.

[0006] It is known to retread the worn treads of tires of conventional wheels comprising an inner tube. Tires used for heavily loaded motor vehicles are particularly concerned by any renovation process making it possible to extend their service life. Thus, it is known to remove the worn tread and replace it with a tread by rolling and fixing it onto the casing of the tire without a tread.

[0007] Other techniques are known for renewing tire treads. For example, document WO-A1-2013086577 describes an apparatus and a method for retreading a worn tire tread. The tread is composed of a thermoplastic elastomer. The apparatus comprises a heating device for heating the worn surface of the tread and a three-dimensional, so-called 3D, printer for applying one or more layers of thermoplastic elastomer to the heated surface. The 3D printer comprises a series of print heads arranged in a row and each configured to follow the profile of the tread.

[0008] However, such a method is designed specifically for retreading conventional wheel tire treads comprising an inner tube. Furthermore, the steps of heating the receiving surface are energy-consuming and expensive and require suitable heating equipment.

[0009] Document FR-B1-3 067 281 proposes a simpler, less energy-consuming process that can be implemented anywhere. This document describes a system for manufacturing a tread for a tire of a tubeless integral wheel. The device comprises a construction robot comprising one or more nozzles for depositing material by addition. The nozzles are arranged side by side and movable laterally in order to be able to cover the entire tread to be constructed.

[0010] However, such a process is particularly slow since the tire is positioned at a given azimuth before the nozzle deposits material and the operation is repeated until the tread is completely manufactured. Such a solution only allows a few tens of grams to be deposited per hour, for example 50g / h.

[0011] Furthermore, the slow manufacturing of the tread can generate seepage problems.

[0012] In order to reduce the tread manufacturing time, large extruders could be provided with material depositing nozzles of 5 mm to 10 mm. However, in this case, although the flow rate of deposited material is higher, of the order of 900 g / h, the precision is much lower.

[0013] All of the proposed solutions are therefore not satisfactory since they require a choice between the speed of manufacturing the tread or the quality of the sculpture of said tread.

[0014] To obtain a high flow rate of deposited material while maintaining good quality of the tread pattern, a large number of extruders could be used, for example between 100 and 200 extruders, each having its own trajectory. However, providing a hundred robot arms each comprising an extruder and arranged around a tire is not feasible in terms of size and manufacturing cost.

[0015] Thus, there is a need to improve the manufacturing devices, in particular the recharging devices, of a tire tread.

[0016] The objective of the invention is to manufacture, in particular to recharge, quickly a tread of a tire while maintaining the quality of the tread pattern.

[0017] We are thus seeking to manufacture a tread in a short time of the order of 10 to 20 minutes and which corresponds to the time required to change a tire. classic by a car professional.

[0018] The present invention relates to a device for additive manufacturing of all or part of a tread of a tire or wheel bandage.

[0019] By "additive manufacturing" we mean a manufacturing process by adding extruded material, called "fused deposition modeling", with the acronym FDM in English terms.

[0020] By "pneumatic" is meant all types of elastic bandages of toric shape subjected to internal pressure or not.

[0021] By "tread" of a tire is meant a quantity of rubber material delimited by lateral surfaces and by two main surfaces, one of which is called the rolling surface, intended to come into contact with a roadway when the tire rolls. The tread comprises a plurality of cutouts or sculptures extending on at least one of the lateral surfaces.

[0022] By "sidewall" of a tire is meant a portion of the lateral surface of the tire disposed between the tread of the tire and a support structure of the wheel. In the case of a tire of a conventional wheel, the sidewall begins from the ends of the cutouts of the tread and extends to a bead of the tire.

[0023] The additive manufacturing device is configured to deposit an extruded material forming the tread on a tire, in particular on a circumferential load-bearing surface or peripheral external contour of said tire.

[0024] The additive manufacturing device comprises a member for driving the tire in rotation, capable of driving said tire in rotation around a horizontal axis of rotation, and at least one ramp for depositing material by addition intended to be arranged above the tire, in particular the tread, and comprising a plurality of material depositing nozzles.

[0025] The material depositing nozzles are each provided with at least one distribution orifice.

[0026] Each of the material depositing nozzles comprises a closure means movable between a closure position and a plurality of opening positions of said dispensing orifice, and an actuator for controlling the movement of the closure means between the closure and opening positions, the closure means being controllable independently of each other.

[0027] Thus, each of the material depositing nozzles is configured to deposit molten material onto the tire, in particular its circumferential bearing surface, which can be rotated continuously or discontinuously around an axis of rotation in a single direction of rotation.

[0028] By "continuous rotation" is meant rotation in a single direction of rotation, without interruption and at constant speed.

[0029] By "discontinuous rotation" is meant a rotation in a single direction of rotation at variable speed during the deposition of material.

[0030] By "open position" of said dispensing orifice is meant a fully open position of the dispensing orifice, but also the intermediate positions in which the dispensing orifice is partially open.

[0031] The opening of the dispensing orifice can advantageously be dependent on the material deposit flow rate. Indeed, controlling the opening of the dispensing orifice makes it possible to manage the material deposit flow rate by varying the position of the closure means, in particular the needle.

[0032] The material depositing nozzles may be identical to each other or different in terms of their dimensions, such as the diameter of the dispensing orifice, their height or their external dimension.

[0033] The additive manufacturing device comprises at least one actuation system configured to move the material depositing ramp in translation relative to the tire in a vertical direction and / or a longitudinal direction parallel to the axis of rotation along the width of the tire, in particular its load-bearing circumferential surface.

[0034] Thus, all of the material depositing nozzles are moved simultaneously, by means of the movement of the material depositing ramp.

[0035] The distribution orifices of each of the nozzles can be closed independently of each other and in a reactive manner, so as to produce any sculpture on the circumferential bearing surface of the tire and in a short time, preferably less than 20 min, preferably less than 15 min.

[0036] The tread is manufactured by depositing the extruded material layer by layer. The extruded material melts onto the previously deposited layer of material and solidifies when the temperature drops.

[0037] For example, the tire may be configured to be mounted on a so-called "conventional" wheel comprising a rim comprising a fixing hub. The tire or pneumatic band is mounted on the rim. The tire comprises a circumferential tread-bearing surface, a tread and two lateral sidewalls surrounding on either side of the tread-bearing surface. The rim is preferably the final rim intended to be mounted on a motor vehicle. The fixing hub forms the fixing interface between the wheel and the vehicle. The tire is subjected to internal pressure via or without an inner tube inflated to a recommended nominal inflation pressure or lower.

[0038] The wheel can be a wheel with or without an inner tube, called “tubeless” in terms Anglo-Saxons comprising an insert made of several layers of expanded plastic to replace the inner tube.

[0039] Alternatively, the tire may be configured to be mounted on a “full” type wheel comprising a radial support structure around which the tire or solid tire is fixed, comprising a support radially external to the support structure. The support extends over the entire circumference of the support structure and comprises an external peripheral contour forming a circumferential surface supporting the tread. The tread is here structurally integrated with the support by means of a tread-supporting surface. The solid tire is not subjected to internal pressure. The radial support structure comprises a fixing hub for fixing the wheel to a vehicle.

[0040] Advantageously, the additive manufacturing device comprises at least one extruder connected to the material depositing ramp and supplying said ramp with a rod of molten material.

[0041] For example, the extruder is associated with all of the material depositing nozzles.

[0042] For example, the extruder is central. Alternatively, another dis position than central for the extruder.

[0043] A single extruder reduces the space around the tire, as well as the manufacturing cost.

[0044] Alternatively, at least one extruder could be provided associated with at least one material depositing nozzle.

[0045] For example, several extruders could be provided, each associated with at least two material depositing nozzles.

[0046] For example, the molten rod can be obtained from granules.

[0047] The material granules are for example made of plastic, for example thermo thermoplastic, acronym TP or thermoplastic elastomer, acronym TPE. The granules of material are therefore hot extruded.

[0048] Alternatively, the molten rod may be obtained from one or more filaments, or even strips. The molten rod may be either fragmented or continuous.

[0049] Preferably, the rod of molten material is continuous and not in the form of successive droplets in order to avoid any defect in the tread pattern.

[0050] Advantageously, each material depositing nozzle comprises a chamber for receiving the molten material coming from the extruder in communication with the distribution orifice.

[0051] The dispensing orifice has, for example, a dimension between 0.6 mm and 1.5 mm, preferably between 0.6 mm and 0.8 mm to produce a deposit of material 1 mm wide and preferably between 1 mm and 1.5 mm to produce a deposit of material 2mm wide.

[0052] For example, the distribution orifice of each of the material depositing nozzles has a rectangular or circular section. A rectangular section makes it possible to improve the level of detail of the tread pattern and the quality of the interruptions by the sealing means.

[0053] For example, the additive manufacturing device comprises a fixed base and one or more material depositing ramps mounted in translation relative to said fixed base.

[0054] For example, the additive manufacturing device comprises at least two material depositing ramps, each associated with its own actuation system and arranged circumferentially around the tire at two given azimuths.

[0055] The shutter frequency of the temporary shutter means is, for example, between 10Hz and 30Hz, for example equal to 20Hz.

[0056] According to one embodiment, each of the temporary sealing means comprises a needle.

[0057] Alternatively, other shutters could be provided, such as, for example, slide shutters or another type of shutter configured to close or open the dispensing orifice.

[0058] The actuator comprises, for example, a piezoelectric device for closing or opening the dispensing orifice of the corresponding nozzle.

[0059] It could also be envisaged to use a pneumatic, magnetic, electric or hydraulic cylinder to close or open the distribution orifice of the corresponding nozzle.

[0060] The needle shutter allows for clean stops of the flow of molten material, without burrs, and clean restarts of said flow. Alternatively, any other shutter system associated with each of the nozzles could be provided, such as for example a valve.

[0061] The additive manufacturing device may comprise a volumetric metering device disposed downstream of the extruder and upstream of the material deposit ramp. For example, the volumetric metering device is a gear pump. The volumetric metering device is configured to deliver a calibrated quantity of molten material onto the carrier surface. Thus, lines of material of constant width can be obtained.

[0062] Thanks to the volumetric dosing device, it is possible to control, in a repeatable manner throughout the manufacture of the object, the quantity of extruded material deposited. Controlling the quantity of extruded material also makes it possible to limit losses of material not necessary for the manufacture of the object.

[0063] According to one embodiment, at least one of the material depositing nozzles is configured to deposit material over all thicknesses of at least one circumferential line of material.

[0064] By deposition of material along a “circumferential line of material” is meant the deposition of material on the bearing surface along a circular path of the wheel.

[0065] By "thickness" is meant a layer of material deposited on a circumferential line of material.

[0066] According to one embodiment, the material depositing nozzles are arranged on the material depositing ramp in a single row in the longitudinal direction.

[0067] In this case, all of the material depositing nozzles are configured to deposit a layer of material during a complete rotation of the tire and said material depositing ramp is configured to be moved in translation along the vertical axis after each complete rotation of the tire.

[0068] During each complete rotation of the tire, each of the material depositing nozzles is configured to deposit molten material along a corresponding material line, and after each complete rotation of the tire, said material depositing ramp is configured to be moved in translation along the vertical axis and so on until the desired tread is obtained.

[0069] By "layer of material" is meant all the circumferential lines of material side by side across the entire width of the tread to be manufactured. A layer of material corresponds to a thickness of deposit of molten material. On a layer of material, it could be provided that material is not deposited on one or more lines in order to produce a particular sculpture shape.

[0070] In the case where the object to be manufactured is cylindrical, a layer corresponds to the set of circumferential lines.

[0071] By “complete rotation” or “full turn” is meant a rotation of the tire of 360°.

[0072] Thus, a full layer is produced at each complete revolution of the tire.

[0073] By "row" is meant an arrangement along the longitudinal axis parallel to the axis of tire rotation. A row is arranged along the width of the tire.

[0074] According to one embodiment, the material depositing nozzles are arranged on the material depositing ramp in at least two rows offset along a transverse axis perpendicular to the axis of rotation and perpendicular to the vertical direction, each row comprising at least two material depositing nozzles aligned in the longitudinal direction.

[0075] In other words, the rows are parallel to each other.

[0076] During each complete rotation of the tire, each material depositing nozzle is configured to deposit molten material along a circumferential line of given material. All material depositing nozzles deposit material in a first layer corresponding to the width of the tread to be manufactured

[0077] After each complete rotation of the tire, the material depositing ramp is configured to be moved in translation relative to the tire along the vertical axis and each of the material depositing nozzles is configured to deposit material along the same circumferential line of given material, to form a second layer superimposed on the first layer, and in which these operations are repeated until the desired thickness of the tread is obtained. Provision could be made for the closing means of certain nozzles to be in the closed position in order to produce a particular sculpture shape.

[0078] Generally, the number of rows depends on the width of the tread to be manufactured.

[0079] According to one embodiment, the width of the material depositing ramp is less than the width of the tread to be manufactured.

[0080] In this case, during each complete rotation of the tire, each material depositing nozzle is configured to deposit material over a thickness along a given circumferential line of material and said material depositing ramp is configured to be moved in translation relative to the tire axially along the longitudinal axis of the width of said ramp after each complete rotation of the tire. These operations are repeated until the first layer of material comprising all of the lines of material is obtained.

[0081] Advantageously, the width of the material depositing ramp is equal to the width of the tread to be manufactured.

[0082] According to another variant, it could be provided that the width of the material depositing ramp is equal to or greater than the width of the tread to be manufactured, but that the density of material depositing nozzles is reduced in order to reduce costs. In this case, after each complete rotation of the tire, the material depositing ramp is configured to be axially offset in translation relative to the tire along the longitudinal axis by the width of a material depositing nozzle as many times as necessary to produce the first layer comprising all of the circumferential lines of material. Here again, each material depositing nozzle is configured to deposit material on several circumferential lines of material during several complete rotations of the tire.

[0083] According to one embodiment, the material depositing nozzles are arranged in the same plane containing a longitudinal axis parallel to the axis of rotation, said nozzles being offset vertically relative to each other.

[0084] In this case, at least one of the material depositing nozzles may be configured to depositing material on all circumferential lines of an entire material layer during several complete rotations of the tire and the material depositing ramp is configured to move only axially in translation relative to the tire along the longitudinal axis of a material line after each complete rotation of the tire.

[0085] The number of material depositing nozzles this time depends on the number of layers to be printed.

[0086] In this case, during a complete rotation of the tire, at least one of the material depositing nozzles of the material depositing ramp is configured to deposit material on a circumferential line of material of a first layer of material. After each complete rotation of the tire, the material depositing ramp is configured to be moved only axially in translation relative to the tire along the longitudinal axis of a line of material. These operations are repeated until at least one of the material depositing nozzles deposits material on an entire first layer of material comprising all of the lines of material.

[0087] Next, the adjacent nozzle is configured to deposit material on a circumferential line of material of a second layer of material superimposed on the first layer. These operations are repeated until the desired tread thickness is obtained.

[0088] The nozzles are for example actuated simultaneously to deposit material along a circumferential line of material onto the lower line of material, then the material depositing ramp is configured to move axially in translation relative to the tire along the longitudinal axis of a circumferential line of material after each complete rotation of the tire, so that the material depositing nozzles manufacture the adjacent line of material and so on until the desired tread pattern is obtained.

[0089] According to another embodiment, the device for additive manufacturing of an object comprises two material depositing ramps each associated with a specific actuation system, said ramps being movable in translation in the longitudinal direction in two opposite directions. The two material depositing ramps are configured to deposit a single layer of material together.

[0090] According to a second aspect, the invention relates to a method for additive manufacturing of all or part of a tread of a tire by a manufacturing device comprising at least one material depositing ramp arranged above the tire, in particular the tread, and comprising a plurality of nozzles for depositing material by addition, each provided with at least one distribution orifice, in which: - the tire is rotated, for example at constant or variable speed, around a horizontal axis of rotation, - each of the material depositing nozzles deposits extruded material onto the rotating tire, in particular its circumferential bearing surface, - closure means each associated with one of the material depositing nozzles are controlled independently of each other to be moved between a closure position and a plurality of opening positions of the distribution orifice of each nozzle according to the tread patterns of the tire to be manufactured, and - after each complete rotation of the tire, the material depositing ramp is moved in translation relative to the tire in a vertical direction and / or a longitudinal direction parallel to the axis of rotation along the width of the tire, in particular its load-bearing circumferential surface.

[0091] According to one embodiment, during each complete rotation of the tire, each material depositing nozzle deposits material along a thickness of at least one given circumferential line of material, and all of the material depositing nozzles deposit material along a first layer corresponding to the width of the tread to be manufactured, and in which, after each complete rotation of the tire, the material depositing ramp is moved in translation relative to the tire along the vertical axis and each of the material depositing nozzles deposits material along the same given circumferential line of material, to form a second layer superimposed on the first layer. These operations are repeated until the desired thickness of the tread is obtained.

[0092] Thus, a full layer is produced at each complete revolution of the tire.

[0093] According to one embodiment, the width of the material depositing ramp is in less than the width of the tread to be manufactured. During each complete rotation of the tire, each material depositing nozzle deposits material to a thickness along a given circumferential line of material. Said material depositing ramp is moved in translation relative to the tire axially along the longitudinal axis by the width of said ramp after each complete rotation of the tire. These operations are repeated until the first layer of material comprising all the lines of material is obtained.

[0094] Thus, each material depositing nozzle deposits material on several lines of material during several complete revolutions of the tire. Then, the material depositing ramp is moved in translation vertically relative to the tire to create the second layer and so on until the desired thickness of the tread is obtained.

[0095] According to another variant, it could be provided that the width of the drop-off ramp of material is at least equal to the width of the tread to be manufactured, but that the density of material depositing nozzles is reduced in order to reduce costs. In this case, after each complete revolution of the tire, the material depositing ramp is offset in translation axially relative to the tire along the longitudinal axis by the width of a material depositing nozzle as many times as necessary to produce the first layer comprising all the circumferential lines of material. Here again, each material depositing nozzle deposits material on several lines of material during several complete revolutions of the tire.

[0096] According to another embodiment, in which the width of the material depositing ramp is at least equal to the width of the tread to be manufactured, during each complete rotation of the tire, at least one of the material depositing nozzles on a circumferential line of material of an entire layer of material. After each complete rotation of the tire, the material depositing ramp is moved only axially in translation relative to the tire along the longitudinal axis of a line of material. These operations are repeated until at least one of the material depositing nozzles deposits material on an entire layer of material comprising all of the lines of material.

[0097] The number of material depositing nozzles this time depends on the number of layers to be printed.

[0098] In this case, during a complete rotation of the tire, the nozzles are actuated simultaneously to deposit material along a circumferential line of material on the lower line of material, then the material depositing ramp is moved in translation axially relative to the tire along the longitudinal axis of a line of material after each complete rotation of the tire, so that the material depositing nozzles deposit material along the adjacent line of material and so on until the desired tread is obtained.

[0099] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0100] [Fig.l] very schematically represents a device for additive manufacturing of a tread according to the invention configured to manufacture a tread on a tire of a wheel according to a first exemplary embodiment;

[0101] [Fig.2] illustrates another example of a wheel on which the additive manufacturing device of [Fig.l] can be used;

[0102] [Fig.3] illustrates a detail of a material deposition nozzle of the additive manufacturing device of [Fig.l] comprising a temporary sealing system according to one embodiment;

[0103] [Fig.4], [Fig.5] schematically represent in detail the additive manufacturing device for a tread of [Fig.l] according to a first embodiment of the invention;

[0104] [Fig.6], [Fig.7] schematically represent in detail the additive manufacturing device for a tread of [Fig.l] according to a second embodiment of the invention;

[0105] [Fig.8], [Fig.9] schematically represent in detail the additive manufacturing device for a tread of [Fig.l] according to a third embodiment of the invention;

[0106] [Fig. 10], [Fig. 11] schematically represent in detail the additive manufacturing device for a tread of [Fig.l] according to a fourth embodiment of the invention; and

[0107] [Fig. 12] schematically represents in detail the additive manufacturing device for a tread of [Fig.l] according to a fifth embodiment of the invention.

[0108] In the remainder of the description, we consider an orthonormal basis X, Y, Z, defined with respect to the additive manufacturing device 10 in which we find:

[0109] - a longitudinal axis X, horizontal and extending from back to front on [Fig.l];

[0110] - a transverse axis Y, horizontal, perpendicular to the longitudinal axis X and extending from left to right on [Fig.l]; and

[0111] - a vertical axis Z, orthogonal to the longitudinal axes X and transverse Y and extending from bottom to top on [Fig.l].

[0112] As illustrated in [Fig.l], a mounted assembly 1 or wheel comprises a rim 2 comprising a fixing hub 3 and a tire 4 or pneumatic bandage mounted on the rim 2. The tire 4 comprises a tread-bearing surface 5, a tread 6 and two lateral sidewalls 7 surrounding the tread-bearing surface 5 on either side, only one of which is visible in [Fig.l].

[0113] The rim 2 is preferably the final rim intended to be mounted on a motor vehicle.

[0114] The fixing hub 3 forms the fixing interface between the wheel 1 and the vehicle.

[0115] The fixing hub 3 here defines a hollow fixing cylinder in which an axis of wheel (not referenced) can be accommodated.

[0116] The tire 4 is here subjected to an internal pressure by means of an inner tube (not shown) inflated to a recommended nominal inflation pressure or lower.

[0117] Alternatively, the mounted assembly 1 could be a tubeless wheel comprising an insert (not shown) made up of several layers of expanded plastic to replace the inner tube.

[0118] The mounted assembly 1 could also be a so-called “airless” tire.

[0119] The tread 6 comprises two lateral surfaces (not referenced), an internal surface (not visible) integral with the tread bearing surface 5 and a rolling surface 6a opposite the internal surface and intended to come into contact with a road surface S when the wheel 1 rolls.

[0120] The tread 6 comprises a plurality of cutouts or sculptures extending on at least one of its lateral surfaces.

[0121] The rim 2 here forms a radial load-bearing structure for the tire 4.

[0122] As illustrated in [Fig.l], a device 10 for additive manufacturing of a tread 6 is configured to deposit an extruded material forming the tread 6 on a load-bearing circumferential surface 5 of the tire 4 of the wheel 1.

[0123] Generally, the device 10 for additive manufacturing of a tread 6 is configured to deposit an extruded material forming the tread 6 on a tire 4. Indeed, it would be possible to provide for the manufacturing of the tread 6 on a tire 4 not mounted on a wheel.

[0124] It would also be possible to provide for the reloading of a new tread 6 onto a worn tread. In this case, the bearing surface corresponds to the worn tread.

[0125] The additive manufacturing device 10 comprises a fixed base 12 and one or more material depositing ramps 20, 30 mounted in translation relative to said fixed base 12.

[0126] In a non-limiting manner, the fixed base 12 comprises a base 14 fixed to the ground S and a vertical arm 16 for fixing the material depositing ramp 20, 30.

[0127] The material depositing ramp 20, 30 is arranged above the wheel 1, and in particular the tread of the tire 4.

[0128] The ramp 20, 30 extends along an extension axis, here the longitudinal axis X.

[0129] The additive manufacturing device 10 comprises an extruder 18 connected to the material depositing ramp 20, 30 and is configured to produce a rod of molten material, for example from granules of material, preferably made of plastic material, for example thermoplastic elastomer, acronym TPE. The granules of material are therefore extruded hot.

[0130] The extruder 18 is here central and feeds said ramp 20, 30 with a rod of molten material from granules. In other words, the central extruder is associated with all of the material depositing nozzles

[0131] Alternatively, the central extruder 18 feeds said ramp 20, 30 with a rod of molten material from one or more filaments, or even strips.

[0132] Alternatively, at least one extruder could be provided associated with at least one material depositing nozzle.

[0133] For example, several extruders could be provided, each associated with at least two material depositing nozzles.

[0134] The tread 6 is manufactured by depositing the extruded material layer by layer on the bearing surface 5 of the tire 4. The extruded material melts on the layer of material deposited previously and solidifies when the temperature drops.

[0135] For this purpose, the material depositing ramp 20, 30 comprises a plurality of nozzles 21, 22, 23, 24; 31, 32, 33, 34, 35, 36, 37, 38 which will be described in detail with reference to FIGS. 3 to 12. Each of the nozzles is configured to deposit the molten material on the bearing surface 5 of the tire 4 mobile in rotation about a horizontal axis of rotation XX.

[0136] Additive manufacturing on a support, here the bearing surface 5 of the tire 4, or more generally the tire 4, placed in continuous rotation makes it possible to manufacture or completely reconstitute the tread 6 over its entire circumference.

[0137] For this purpose, the additive manufacturing device 10 comprises a member 15 for driving the tire 4 in rotation around the axis of rotation XX.

[0138] As illustrated in [Fig.l], the rotation drive member 15 is in the form of a rotating drum or cylinder cooperating with the wheel hub 3 and configured to drive the tire 4 in rotation via the wheel hub 3.

[0139] Alternatively, it could be provided that the rotation drive member comprises rollers arranged under the wheel to rotate said wheel by friction in the case of a tire mounted on a wheel.

[0140] According to another variant, a rotation drive member could be provided configured to act directly on the sidewalls 7 of the tire 4.

[0141] These variants are interesting in the case where it is necessary to manufacture the tread 2 without removing the wheel 1 from the vehicle.

[0142] The additive manufacturing device 10 further comprises an actuation system (not shown) configured to move the material depositing ramp 20, 30 relative to the wheel 1 in a vertical direction Z and / or a longitudinal direction X parallel to the axis of rotation XX along the width of the wheel 1. Thus, all of the nozzles are moved simultaneously at the same time as the movement of the material deposit ramp 20, 30.

[0143] The device 10 for additively manufacturing a tread can also be used to manufacture or refill a tread 6' on a bearing surface 5' of a tire 4' of a full wheel 1' as illustrated in [Fig.2].

[0144] The integral wheel 1' here comprises a radial supporting structure 2' around which is fixed a tire 4' or solid bandage comprising a support 7' radially external to the supporting structure 2'. The support 7' extends over the entire circumference of the supporting structure 2' and carries the tread 6'. The tread 6' is here structurally integrated with the support 7' by means of a tread-bearing surface 5' forming a peripheral external contour of the radial supporting structure 2'.

[0145] The solid bandage 4' is not subjected to internal pressure.

[0146] As illustrated in [Fig.2], the radial supporting structure 2' comprises a fixing hub 3' for fixing the wheel 1' to a vehicle.

[0147] The fixing hub 3' here defines a hollow fixing cylinder in which a wheel axle (not shown) can be housed.

[0148] The radial supporting structure 2' is, for example, made of glass fiber reinforced plastic material.

[0149] The supporting structure 2' here comprises a plurality of sticks or stays 8' connecting the hub 3' to the support 7'.

[0150] As illustrated in [Fig.2], the supporting structure 2' comprises five sticks 8'. Alternatively, a number of sticks 8' between three and nine could be provided.

[0151] Openings or windows 9' are defined between two adjacent sticks 8'. The openings 9' are here regularly distributed circumferentially.

[0152] The openings 9' here have ovoid profiles. Alternatively, other profile shapes could be provided for the openings 9'.

[0153] The supporting structure 2' and the support 7' here comprise a network or a three-dimensional structure of beams or lattices.

[0154] Alternatively, it could be provided that the radial supporting structure 2' comprises a plurality of slats arranged radially to support the tire 4' and in particular the support 7'.

[0155] As illustrated in [Fig.3], each material depositing nozzle or jet 21, 22, 23, 24; 31, 32, 33, 34, 35, 36, 37, 38 comprises a chamber 25 for receiving the molten material coming from the central extruder 18 and a distribution orifice 26 in communication with the chamber 25.

[0156] The dispensing orifice 26 has a dimension between 0.6 mm and 1.5 mm, preferably between 0.6 mm and 0.8 mm to produce a deposit of material 1 mm wide and preferably between 1 mm and 1.5 mm to produce a deposit of material 2 mm wide. wide.

[0157] The distribution orifice 26 of each of the nozzles has a rectangular or circular section. A rectangular section makes it possible to improve the level of detail of the sculpture and the quality of the interruptions.

[0158] Each of the material depositing nozzles 21 to 24; 31 to 38 comprises a closure device 28 comprising a closure means 28a movable between a closure position and an opening position of the dispensing orifice 26, and an actuator 28b for controlling the movement of the closure means 28a between the closure and opening positions. The closure means 28a are controllable independently of each other.

[0159] Thus, each nozzle comprises its own closure means 28 configured to interrupt the flow of molten material through the dispensing orifice 26 of the corresponding nozzle.

[0160] Each of the nozzles can be interrupted independently and reactively, so as to generate any sculpture on the wheel 1 and in a short time, preferably less than 20 min, preferably less than 15 min.

[0161] Such a loading duration corresponds to a material deposit rate of between 10 kg / h and 20 kg / h, preferably equal to 12 kg / h.

[0162] The shutter frequency is between 10Hz and 30Hz, for example equal to 20Hz.

[0163] In the example illustrated in [Fig.3], the closure means 28a is in the form of a needle actuated by the actuator 28b.

[0164] The actuator 28b comprises, for example, a piezoelectric device (not re presented) to close or open the dispensing orifice 26 of the corresponding nozzle.

[0165] The needle shutter 28a makes it possible to achieve clean stops in the flow of molten material, without burrs, and clean restarts of said flow.

[0166] Alternatively, any other means of closure associated with each of the nozzles could be provided, such as for example a valve.

[0167] According to a non-limiting example, the additive manufacturing device 10 may comprise a volumetric dosing device (not shown) arranged downstream of the central extruder and upstream of the material depositing ramp 20, 30.

[0168] For example, the volumetric metering device is a gear pump. The volumetric metering device is configured to deposit a calibrated quantity of molten material onto the bearing surface 5, 5' of the tire 4, 4'. Thus, lines of material of constant width can be obtained, unlike the deposit of material in the form of successions of droplets known from the prior art.

[0169] The terms “downstream” and “upstream” are defined by considering the direction of circulation of the material.

[0170] An example of a material depositing ramp 20 is illustrated with reference to FIGS. 4 and 5.

[0171] In this example, the material depositing ramp 20 is configured to deposit extruded material forming the tread 6, 6' on the tire 4, 4', in particular its circumferential bearing surface 5, 5', along circumferential lines of material Li.

[0172] By deposition of material along a “circumferential line of material” Li, we mean the deposition of material along a circular trajectory of the tire 4, 4', with i ranging from 1 to x, x being the total number of lines of material.

[0173] By "layer of material" Cj is meant all the circumferential lines of material Li side by side over the entire width of the tread 6, 6' to be manufactured, with j ranging from 1 to y, y being the total number of layers of material to form the total thickness of the desired tread 6, 6'.

[0174] A layer of material C corresponds to a thickness of deposit of molten material.

[0175] By “row” R, we mean an arrangement along the longitudinal axis X parallel to the axis of rotation XX of the tire 4, 4' and perpendicular to the vertical direction Z. A row R is arranged along the width of the tire 4, 4', in particular its bearing surface 5, 5'.

[0176] As illustrated in Figures 4 and 5, the material depositing ramp 20 comprises a plurality of material depositing nozzles 21, 22, 23, 24, here twenty-four in number, each intended to construct all the thicknesses or layers of at least one circumferential line of material Li.

[0177] By “thickness” is meant a layer of material deposited on a material line.

[0178] As illustrated, the number of material depositing nozzles is, here, twenty-four and the number of lines of matter Li is here equal to twenty-four. We therefore have i between one and twenty-four.

[0179] Alternatively, a different number of material depositing nozzles could be provided.

[0180] As illustrated, the number of layers of material Cj is, here, six. We therefore have j between one and six.

[0181] Alternatively, a different number of layers of material Cj could be provided.

[0182] As illustrated, the material depositing ramp 20 has a width equal to the tread width 6.6' to be manufactured.

[0183] During the continuous rotation of the tire 4,4' under the material depositing ramp 20, each of the material depositing nozzles is actuated to deposit material on a given circumferential line of material Li. The first nozzle 24 deposits material on a first line L1, the second nozzle 23, adjacent to the first nozzle 24, simultaneously deposits material on a second line L2, adjacent to the first line L1 and so on until the entire layer comprising the set of adjacent circumferential lines Li.

[0184] Thus, a full layer is produced at each complete rotation of the tire 4, 4'. After each complete rotation of the tire, the material depositing ramp 20 is moved in translation relative to the tire 4, 4' along the vertical axis Z and each of the material depositing nozzles 21, 22, 23, 24 is actuated to deposit molten material along the same circumferential line of given material Li, to form the second layer. These operations are repeated until the desired thickness of the tread 6, 6' is obtained.

[0185] In the example illustrated in Figures 4 and 5, a single material depositing nozzle 21, 22, 23, 24 is configured to build all thicknesses of a given circumferential line of material Li.

[0186] The material depositing nozzles 21, 22, 23, 24 are here arranged on the material depositing ramp 20 in rows RI, R2, R3, R4 offset along the transverse axis Y.

[0187] Indeed, it may be necessary to provide a distance of 4 mm between each material depositing nozzle.

[0188] As illustrated, the material depositing ramp comprises four rows R1, R2, R3, R4 each comprising six material depositing nozzles 21, 22, 23, 24. Alternatively, a different number of rows could be provided, for example greater than or equal to two. A different number of nozzles could also be provided per row R.

[0189] The number of rows R depends on the width of the tread 6, 6' to be manufactured.

[0190] Alternatively, it could also be provided that the material depositing nozzles 21, 22, 23, 24 are arranged on the material depositing ramp 20 in a single row RI in the longitudinal direction X.

[0191] Alternatively, it could be provided that the material depositing ramp 20 has a width different from the tread 6, 6' to be manufactured.

[0192] For example, it could be provided that the material depositing ramp 20 has a width less than the width of the tread 6, 6' to be manufactured. In this case, during each complete rotation of the tire 4, 4', each material depositing nozzle 21 to 24 deposits material over a thickness along a given circumferential line of material Li and after each complete revolution of the tire 4, 4', the material depositing ramp 20 is moved in translation relative to the tire 4, 4' axially along the longitudinal axis X by the width of said ramp 20, as many times as necessary to manufacture the first layer comprising all of the lines of material Li.

[0193] After the manufacture of each layer comprising all the lines of material Li, the material depositing ramp 20 is moved in translation relative to the tire 4, 4' along the vertical axis Z and the operation of manufacturing a layer is repeated.

[0194] These operations are repeated until all the superimposed layers forming the desired thickness of the tread 6, 6' are obtained.

[0195] For example, for a bearing surface 5, 5' having a width of 225mm, and a material depositing ramp 20 of 80mm width, the tire 4, 4' is rotated over three complete revolutions and during each complete revolution, the material depositing ramp 20 is offset along the longitudinal axis X by 80mm.

[0196] Thus, each material depositing nozzle 21, 22, 23, 24 deposits material on several circumferential lines of given material Li during several complete revolutions of the tire 4, 4'.

[0197] According to another variant, it could be provided that the width of the material depositing ramp 20 is equal to or greater than the width of the tread 5, 5' to be manufactured, or more generally than the width of the bearing surface 5, 5', but that the density of material depositing nozzles is reduced in order to reduce costs. In this case, after each complete revolution of the tire 4, 4', the material depositing ramp 20 is offset in translation axially relative to the tire 4, 4' along the longitudinal axis X by the width of a material depositing nozzle 21, 22, 23, 24 as many times as necessary to produce the first layer C1 comprising all the lines of material Li. After the manufacture of each layer comprising all the lines of material Li, the material depositing ramp 20 is moved in translation relative to the tire 4, 4' along the vertical axis Z and the operation of manufacturing a layer is repeated.

[0198] These operations are repeated until all the superimposed layers forming the desired thickness of the tread 6, 6' are obtained.

[0199] Again, each material depositing nozzle deposits material on several lines of material during several complete revolutions of the tire 4, 4'.

[0200] However, such a variant increases the total manufacturing time of the tread.

[0201] As illustrated, the additive manufacturing device 10 comprises a single material deposit ramp 20 around the tire 4, 4'.

[0202] Alternatively, it could be provided that the additive manufacturing device 10 comprises at least two material depositing ramps 20 each associated with a specific actuation system and arranged circumferentially around the tire at two given azimuths.

[0203] For example, a first ramp could be provided at a given first azimuth and a second ramp arranged at 180° from the first ramp. Alternatively, the second ramp could be arranged relative to the first ramp at an angle of between 10° and 350°, preferably between 30° and 320°.

[0204] Alternatively, a different number of ramps could be provided, for example greater than or equal to three, each associated with its own actuation system and arranged circumferentially around the tire at three given azimuths.

[0205] Another example of a material depositing ramp 30 is illustrated with reference to FIGS. 6 and 7.

[0206] In this example, the material depositing ramp 30 is configured to deposit extruded material forming the tread 6, 6' on the tire 4, 4', in particular its circumferential bearing surface 5, 5', in layers of material Cj.

[0207] In this example, the width of the material depositing ramp 30, 30a, 30b is equal to the width of the tread 6, 6' to be manufactured and each material depositing nozzle 31 to 38 is configured to build an entire material layer Cj.

[0208] During each complete rotation of the tire, one of the material depositing nozzles of the material depositing ramp 30 deposits material on a circumferential line of material Li of a layer of material Cj. After each complete rotation of the tire 4, 4', the material depositing ramp 30 is moved in translation only axially relative to the tire 4, 4' along the longitudinal axis X of a line of material Li. These operations are repeated until each material depositing nozzle 31 to 38 deposits material on an entire layer of material Cj comprising all of the lines of material Li.

[0209] In other words, during a complete rotation of the tire 4, 4', the nozzles 31 to 38 are actuated successively to produce a given circumferential line of material Li. The first nozzle 31 deposits material on a first line L8 according to a first thickness, then the material depositing ramp 30 is moved axially relative to the tire 4, 4' along the longitudinal axis X by the width of a line of material Li, the first nozzle 31 deposits material on a second line L7 and the second nozzle 32, adjacent to the first nozzle 31, deposits material on the first line L8 according to a second layer thickness superimposed on the first line formed by the first nozzle and so on until each material depositing nozzle produces a given layer Cj until the desired tread pattern 6, 6' is obtained.

[0210] Thus, the first material deposition nozzle 31 produces the first layer C1, the second nozzle 32 produces the second layer C2, the third nozzle 33 produces the third layer C3, and so on until the desired total thickness of the tread 6, 6' is obtained. Each of the material deposition nozzles 31 to 38 is therefore configured to construct an entire material layer Cj.

[0211] The layers Cj are constructed in this way with a delay on the previous layer.

[0212] Such an arrangement allows fewer material depositing nozzles to be used than the material deposition with nozzles configured to deposit material along a material line Li.

[0213] In this embodiment, the material depositing ramp 30 is not moved in translation along the vertical axis Z.

[0214] The number of material depositing nozzles 31 to 38 depends this time on the number of layers of material to be constructed.

[0215] The material depositing nozzles 31 to 38 are here arranged in rows RI, R2, R3, R4 offset along the vertical axis Z.

[0216] Indeed, it may be necessary to provide a distance of 4 mm between each material depositing nozzle.

[0217] As illustrated, the material deposition ramp comprises eight material deposition nozzles 31 to 38. Alternatively, a different number of material deposition nozzles could be provided, for example greater than or equal to six.

[0218] As illustrated, the number of lines of material Li is equal to eight. Alternatively, a different number of lines of material Li could be provided. The number of lines of material depends on the width of the tread 6, 6' to be produced.

[0219] As illustrated, the number of layers of material Cj is equal to eight. Alternatively, a different number of layers of material Cj could be provided. The number of layers of material Cj depends on the total thickness of the tread 6, 6' to be manufactured.

[0220] Taking for example a layer thickness Cj of 0.8mm for 8mm of total thickness of the tread to be manufactured, ten material deposition nozzles can be used.

[0221] However, the rotation speed of the tire 4, 4' and the frequency of closing of the nozzles are higher than with nozzles configured to deposit the material along a line of material Li, as described in detail with reference to FIGS. 3 and 4.

[0222] In the example illustrated in Figures 6 and 7, the material depositing nozzles 31 to 38 deposit material on the same material line Li with an offset along the longitudinal axis X.

[0223] As illustrated, the nozzles 31 to 38 are also offset along the vertical axis Z, so that it is no longer necessary to move the material depositing ramp vertically relative to the tire 4, 4'.

[0224] The embodiment illustrated in Figures 8 and 9 in which the same elements bear the same references, differs from the embodiment illustrated in Figures 6 and 7 only by the fact that the layers Cj are constructed with two turns of delay on the previous layer.

[0225] As illustrated in Figures 8 and 9, the material deposition ramp 30 comprises eight material deposition nozzles 31 to 38. Alternatively, a different number of material deposition nozzles could be provided, for example greater than or equal to six.

[0226] As illustrated, the number of lines of material is equal to fifteen Li. Alternatively, a different number of lines of material Li could be provided. The number of lines of material depends on the width of the tread 6, 6' to be produced.

[0227] As illustrated, the number of layers of material Cj is equal to eight. Alternatively, a different number of layers of material Cj could be provided. The number of layers of material Cj depends on the total thickness of the tread 6, 6' to be manufactured.

[0228] The embodiment illustrated in Figures 10 and 11 in which the same elements have the same references, differs from the embodiment illustrated in Figures 8 and 9 only in that two material depositing nozzles 31a, 31b to 38a, 38b are configured to build up an entire layer of material comprising all the adjacent circumferential lines Li over a thickness. The layers of material Cj are built up with two turns of delay on the previous layer.

[0229] As illustrated in Figures 10 and 11, the material depositing ramp 30 comprises sixteen material depositing nozzles 31a, 31b to 38a, 38b. Alternatively, a different number of material depositing nozzles could be provided, for example greater than or equal to eight.

[0230] As illustrated, the number of lines of material is equal to twenty-three. Alternatively, a different number of lines of material could be provided. The number of lines of material depends on the width of the tread 6, 6' to be produced.

[0231] As illustrated, the number of layers of material Cj is equal to eight. Alternatively, a different number of layers of material Cj could be provided. The number of layers of material Cj depends on the total thickness of the tread 6, 6' to be manufactured.

[0232] The embodiment illustrated in [Fig. 12] in which the same elements bear the same references, differs from the embodiment illustrated in Figures 8 and 9 only by the fact that the additive manufacturing device 10 comprises two material depositing ramps 30a, 30b.

[0233] The additive manufacturing device 10 comprises a first actuation system (not shown) configured to move in translation a first material depositing ramp 30a relative to the tire 4, 4' in the longitudinal direction X parallel to the axis of rotation XX along the width of the tire 4, 4' in a first direction.

[0234] The additive manufacturing device 10 comprises a second actuation system (not shown) configured to move in translation a second material depositing ramp 30b relative to the wheel 1, 1' in the longitudinal direction X along the width of the tire 4, 4' in a second direction.

[0235] The first meaning is opposite to the second meaning.

[0236] The two material depositing ramps 30a, 30b are thus configured to be moved along the longitudinal axis X relative to the tire 4, 4' in the opposite direction. starting from the middle of the tire 4, 4'. The two material depositing ramps 30a, 30b are configured to deposit material together on a single layer Cj.

[0237] Each ramp 30a, 30b corresponds to one of the ramps described with reference to FIGS. 6 to 11.

[0238] As illustrated in [Fig. 12], each material depositing ramp 30a, 30b comprises eight material depositing nozzles (not referenced). Alternatively, a different number of material depositing nozzles could be provided, for example greater than or equal to six.

[0239] As illustrated, the number of lines of material Li is equal to sixteen. Alternatively, a different number of lines of material could be provided. The number of lines of material depends on the width of the tread 6, 6' to be produced.

[0240] As illustrated, the number of layers of material Cj is equal to four. Alternatively, a different number of layers of material Cj could be provided. The number of layers of material Cj depends on the total thickness of the tread 6, 6' to be manufactured.

[0241] In all embodiments, it could be provided that the means for closing certain nozzles is in the closed position in order to produce a particular sculptural shape of the object to be manufactured.

[0242] The multi-nozzle material deposit ramp allows the deposit of material at selected locations and thus to produce a good quality tread pattern.

Claims

Claims

1. Device (10) for additive manufacturing of all or part of a tread (6, 6') of a tire (4, 4'), comprising: - a member (15) for driving the tire in rotation, capable of driving said tire around a horizontal axis of rotation (XX), and - at least one ramp (20, 30, 30a, 30b) for depositing material by addition intended to be arranged above the tread of the tire and comprising a plurality of material depositing nozzles (21 to 24; 31 to 38) each provided with at least one distribution orifice (26), characterized in that - each of the material depositing nozzles (21 to 24;31 to 38) comprising a closure means (28a) movable between a closure position and a plurality of opening positions of said dispensing orifice (26), and an actuator (28b) for controlling the movement of the closure means (28a) between the closure and opening positions, - the closure means (28a) being controllable independently of each other, and in that - the device (10) comprises at least one actuating system configured to move the material depositing ramp (20, 30, 30a, 30b) in translation relative to the tire in a vertical direction (Z) and / or a longitudinal direction (X) parallel to the axis of rotation (XX) along the width of the tire (4, 4'), all of the material depositing nozzles (21 to 24; 31 to 38) being moved simultaneously and, this by means of the movement of the material depositing ramp depositing material (20, 30, 30a, 30b) relative to the tire.;

2. Device (10) according to claim 1, comprising at least one extruder (18) connected to the material depositing ramp (20, 30, 30a, 30b) and supplying said ramp (20, 30, 30a, 30b) with a rod of molten material.

3. Device (10) according to claim 2, in which the extruder (18) is associated with the set of material depositing nozzles.

4. Device (10) according to claim 2, comprising a plurality of extruders, each associated with at least two material depositing nozzles.

5. Device (10) according to any one of claims 2 to 4, in wherein each material depositing nozzle (21 to 24; 31 to 38) comprises a chamber (25) for receiving the molten material coming from the extruder (18) in communication with the distribution orifice (26).

6. Device (10) according to any one of the preceding claims, in which the dispensing orifice (26) of each of the material depositing nozzles (21 to 24; 31 to 38) has a rectangular or circular section.

7. A device (10) according to any preceding claim, wherein each of the sealing means (28a) comprises a needle.

8. Device (10) according to any one of the preceding claims, in which the material depositing nozzles (21, 22, 23, 24) are arranged on the material depositing ramp (20) in a single row (RI, R2, R3, R4) in the longitudinal direction (X).

9. Device (10) according to any one of claims 1 to 7, wherein the material depositing nozzles (21, 22, 23, 24) are arranged on the material depositing ramp (20) in at least two parallel rows (RI, R2, R3, R4) offset along a transverse axis (Y) perpendicular to the axis of rotation (XX) and perpendicular to the vertical direction (Z), each row (RI, R2, R3, R4) comprising at least two material depositing nozzles aligned along the longitudinal direction (X).

10. Device (10) according to any one of claims 1 to 7, in which the material depositing nozzles (31 to 38) of the material depositing ramp (30, 30a, 30b) are arranged in the same plane comprising a longitudinal axis (X) parallel to the axis of rotation (XX), said nozzles (31 to 38) being vertically offset relative to each other.

11. Device (10) according to claim 10, comprising two material depositing ramps (30a, 30b) each associated with its own actuation system, said ramps being movable in translation in the longitudinal direction (X) in two opposite directions.

12. Method for additive manufacturing of all or part of a tread (6, 6') of a tire (4, 4') by a manufacturing device comprising at least one material depositing ramp (20, 30, 30a, 30b) arranged above the tread of the tire and comprising a plurality of material depositing nozzles (21 to 24; 31 to 38) by addition each provided with at least one distribution orifice (26), in which: - the tire (1, 1') is rotated around a horizontal axis of rotation (XX), - each of the material depositing nozzles (21 to 24; 31 to 38) deposits extruded material onto the rotating tire (4, 4'), - closing means (28a) each associated with one of the material depositing nozzles (21 to 24; 31 to 38) are controlled independently of each other to be moved between a closing position and a plurality of opening positions of the distribution orifice (26) of each nozzle according to the tread patterns of the tire to be manufactured, and - after each complete rotation of the tire, the material depositing ramp (20, 30, 30a, 30b) is moved in translation relative to the tire in a vertical direction (Z) and / or a longitudinal direction (X) parallel to the axis of rotation (XX) along the width of the tire (4, 4'), all of the material depositing nozzles (21 to 24; 31 to 38) being moved simultaneously and this by means of the movement of the material depositing ramp (20, 30, 30a, 30b) relative to the tire.

13. The method of claim 12, wherein: - during each complete rotation of the tire (4, 4'), each material depositing nozzle (21 to 24) deposits material along a thickness of at least one given circumferential line of material (Li), and all of the material depositing nozzles (21 to 24) deposit material along a first layer corresponding to the width of the tread to be manufactured, and in which - after each complete rotation of the tire (4, 4'), the material depositing ramp (20) is moved in translation relative to the tire (4, 4') along the vertical axis (Z) and each of the material depositing nozzles (21 to 24) deposits material along the same given circumferential line of material (Li), to form a second layer superimposed on the first layer, and in which these operations are repeated until the desired thickness of the tread (6, 6') is obtained.

14. A method according to claim 13, wherein the width of the material depositing ramp (20) is less than the width of the tread (6, 6') to be manufactured, and wherein during each complete rotation of the tire (4, 4'), each material depositing nozzle (21 to 24) deposits material over a thickness along a given circumferential line of material, wherein said material depositing ramp (20) is moved in translation relative to the tire (4, 4') axially along the longitudinal axis (X) by the width of said ramp (20) after each complete rotation of the tire (4, 4'), and wherein these operations are repeated until the first layer of material (Cj) comprising all of the lines of material (Li) is obtained.

15. A method according to claim 12, wherein the width of the material depositing ramp (20) is at least equal to the width of the tread (6, 6') to be manufactured, during each complete rotation of the tire (4, 4'), at least one of the material depositing nozzles (31 to 38) of the material depositing ramp (30, 30a, 30b) deposits material on a circumferential line of material (Li) of a layer of material (Cj), wherein, after each complete rotation of the tire (4, 4'), the material depositing ramp (30) is moved only axially in translation relative to the tire (4, 4') along the longitudinal axis (X) of a line of material (Li) and wherein these operations are repeated until at least one of the material depositing nozzles (31 to 38) deposits material on an entire layer of material (Cj) comprising the set of material lines (Li).

Images