Tooling with a receiving surface comprising a plurality of passages for manufacturing a molded object on said receiving surface

Abstract

Tooling (1) for manufacturing a toroidal bandage (100) comprising a crown (101), a first annular bead (102) and a second annular bead (103), as well as a first flank (104) and a second flank (105), said tooling (1) comprising a core (10) provided with grooves (15) intended to receive reinforcing elements (108) designed to permanently integrate the structure of the bandage (100) and each extend into the cavity (107) of the bandage by connecting a top anchoring point (109) located in the crown (101) of the bandage to a lateral anchoring point (110) located in one of the flanks (104, 105) or the beads (102, 103) of the bandage (100). The tool (1) comprises an anti-penetration system (30) comprising a circuit for supplying a pressurized fluid into the grooves (15) of the core (10) and a system for injecting said pressurized fluid during a step of baking the bandage (100). Figure for the abstract: Fig 2A

Description

Title of the invention: Tooling with a receiving surface comprising a plurality of passages for manufacturing a molded object on said receiving surface. Technical field of the invention

[0001] The present invention relates to the general field of manufacturing an object molded on a receiving surface of a tool.

[0002] More particularly, the surface for receiving the tooling is perforated and comprises a plurality of passages or orifices.

[0003] According to a particular application, the invention relates to the field of the manufacture of toroidal tires, and more particularly of pneumatic tires intended to equip the wheels of a vehicle.

[0004] By "tire" is meant a bandage intended to form a cavity by cooperating with a mounting support, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure. A tire according to the invention has a structure of substantially toroidal shape of revolution around a main axis of the tire, this main axis being coincident with the axis of rotation of the tire. State of the prior art

[0005] Generally, a tire comprises a crown having two axial ends each extended, radially inwards, by a sidewall then by a bead intended to come into contact with a rim. The assembly delimits an internal toric cavity.

[0006] More specifically, the crown comprises, radially from the outside to the inside, a tread, intended to come into contact with the ground via a rolling surface, and a crown reinforcement intended to ensure the reinforcement of the crown of the tire. A carcass reinforcement connects the two sidewalls together and is anchored, in each bead, to a circumferential reinforcement element, most often of the bead wire type.

[0007] In order to improve the behavior, in particular the drift resistance, of the pneumatic tires, the Applicant had the idea of ​​implanting a stiffening structure within the toric inflation cavity that delimits the tire.

[0008] Reference may be made in this regard to documents WO 2019 / 115917 - Al and WO 2020 / 128225-AL

[0009] The tire described in these documents comprises a crown extended radially inwards respectively on each side of the median plane of the tire by first and second sidewalls then by first and second beads intended to come into contact with a mounting support, for example a rim. Each first and second bead comprises a circumferential reinforcing element intended to allow the tire to be attached to the mounting support.

[0010] The tire comprises an internal surface delimiting a toric inflation cavity of the tire once the latter is mounted on the mounting support.

[0011] The tire described in these documents comprises a stiffening structure comprising first stiffening wire elements extending continuously in the toric cavity from the first bead to the crown and second stiffening wire elements extending continuously in the toric cavity from the second bead to the crown.

[0012] Each first and second wire stiffening element is secured to each bead from which it extends by a bead interface between the wire stiffening element and a portion of the inner surface of the bead. Similarly, each first and second wire stiffening element is secured to the crown of the tire by a crown interface between the wire stiffening element and a portion of the inner surface of the crown.

[0013] These stiffening wire elements are usually called "stays". The advantage of using stiffening wire elements is to have a stiffening structure with low mass and low hysteresis. The use of identical stiffening wire elements allows for a homogeneous distribution of forces between the stiffening elements.

[0014] However, in order to produce such stay bandages, the Applicant has developed specific manufacturing tools.

[0015] In this regard, reference may be made to document FR 3 120 814 - Al which proposes a grooved core tool for the manufacture of pneumatic tires reinforced by stays which pass through the inflation cavity.

[0016] The tooling described in this document comprises a core provided with groove-type passages intended to receive reinforcing elements, called "stays" which are designed to permanently integrate the structure of the bandage and each extend into the cavity of the bandage by connecting a top anchoring point located in the top of the bandage to a lateral anchoring point located in one of the sides or beads of the bandage.

[0017] The use of such a core makes it possible to position the stays at the desired locations within the volume reserved by the core and consequently in the region of the space which will subsequently become the bandage cavity after the bandage has been formed and the core removed.

[0018] However, during the step of curing the bandage, during which the components of the wall of said bandage are vulcanized, the bandage is inserted into the grooves of the core during the increase in pressure in the curing mold.

[0019] The internal volume of the curing mold available to accommodate the tire then becomes larger than desired, the tire therefore has more room to expand freely and the internal pressure in the curing mold cannot reach the pressure necessary for manufacturing the tire.

[0020] In fact, the molding pressure is obtained by expansion of the core of the manufacturing tool and the bandage during the baking step.

[0021] It is therefore essential that the volume of the bandage is perfectly adapted to the volume of the cooking mold in order to achieve a necessary molding pressure of between 50 bars and 60 bars, preferably equal to 55 bars.

[0022] Without such molding pressure, the bandage is not pressed against the mold and may have appearance defects. Furthermore, the individual bandage segments will not be sufficiently brought into contact with each other, so that the adhesion between the bandage segments may prove insufficient.

[0023] In addition, the bandage calls inside the grooves can cause aesthetic problems inside the envelope, but also structural problems, such as the displacement of the carcass threads.

[0024] Document FR 3 120 814 - Al proposes a solution for filling grooves using mechanical devices. However, such a solution is difficult to apply industrially.

[0025] There is a need to remedy the aforementioned drawbacks and to improve existing solutions to prevent the rubber constituting the bandage from penetrating into the grooves of a grooved core of a tool for manufacturing a strut tire. Description of the invention

[0026] The invention aims to prevent the materials constituting the object from flowing into the passages made in a tool comprising an openwork receiving surface.

[0027] More particularly, the invention also aims to prevent the components constituting the raw bandage or the rubber from creeping into the grooves of the molding inner part, called "PIM" or core of the tire.

[0028] The invention relates to a tool intended for the manufacture of an object comprising a wall having an internal surface which delimits a cavity, the tool comprising a receiving surface having a shape conjugated to the internal surface of the wall of the object and comprising a plurality of passages which extend under the surface of reception, and which open onto said reception surface, the object being intended to be molded on the reception surface of the tooling.

[0029] The tooling comprises an anti-penetration system configured to control the penetration of the material constituting the object into the passages, the anti-penetration system comprising a circuit for supplying a pressurized fluid into the passages and a system for injecting said pressurized fluid during a step of cooking the object.

[0030] Such tooling makes it possible to mold objects on receiving surfaces or molding surfaces comprising passages or orifices.

[0031] According to a particular embodiment of the invention, the object is a toroidal bandage of a tire forming the object and the tooling is configured to manufacture said toroidal bandage.

[0032] According to one embodiment, the toroidal bandage comprises a crown intended to form a tread, a first annular bead and a second annular bead designed to allow the bandage to be attached to a mounting support, such as a rim, as well as a first sidewall and a second sidewall which connect the crown respectively to the first bead and to the second bead, the crown, the first and second sidewalls and the first and second beads forming as a whole a wall having a concave internal surface which delimits a cavity of the bandage.

[0033] Said tooling comprises a toroidal core having, around its central axis, a convex external surface called the “receiving surface” which has a shape conjugated to the internal surface of the wall of the bandage and which comprises for this purpose a radially external top zone, intended to receive components constituting the top of the bandage, and, on either side axially of said top zone, a first lateral zone folded back towards the central axis and intended to receive components constituting the first flank and the first bead as well as a second lateral zone folded back towards the central axis and intended to receive components constituting the second flank and the second bead, so that the core materializes a volume, called the “reserved volume”, which is delimited externally by the receiving surface and which corresponds to the cavity of the bandage.

[0034] The core comprises a plurality of passages which extend inside the reserved volume, under the receiving surface, and which open onto said receiving surface in such a way that each of said passages connects the top zone of the receiving surface to one of the first and second lateral zones so that the core can receive, inside said passages, reinforcing elements, called "stays", which are designed to permanently integrate the structure of the bandage and each extend into the cavity of the bandage by connecting a top anchoring point located in the top of the bandage to a lateral anchoring point located in one of the flanks or beads of the bandage.

[0035] The tooling comprises an anti-penetration system which cooperates with the core to prevent penetration of the constituent components of the crown, sides or beads of the tire into the passages of the core in which the stays are engaged.

[0036] The anti-penetration system comprises a circuit for supplying a pressurized fluid into the passages of the core and a system for injecting said pressurized fluid during a step of curing the bandage.

[0037] The anti-penetration system prevents materials, and in particular rubber-based compositions, present in the components of the tire from penetrating into the grooves by fining, in order to prevent the formation of rubber burrs which would cause the stays to stick to the walls of the grooves, and which would therefore create a risk of the stays being torn off when the angular sectors of the core are extracted.

[0038] The injection under pressure of a fluid into the grooves makes it possible to prevent, or substantially slow down, the penetration into the groove of the constituent materials of the components of the bandage, and in particular of mixtures based on unvulcanized rubber.

[0039] When baking on a hard core of the manufacturing tool, the molding pressure is obtained by the difference between the molding volume and the contained components of the bandage. This balance evolves according to the expansions. In practice, the increase in the temperature of the molding inner part and of the components of the bandage causes an increase in pressure. The leaks of the components of the bandage through the vents moderate this increase in pressure, but the grooves of the stays offer openings that are too large and the loss of volume caused causes the pressure to drop.To maintain it at a level satisfying the cooking requirements, it is essential to inject a fluid at the grooves at a progressive pressure increasing until reaching a pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, in a linear manner to reach a first pressure of between 20 bars and 35 bars for a first duration of between 50s and 100s, for example equal to 60s, then following a second slope for a second duration of between 120s and 200s, for example equal to 150s, to reach a molding pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, preferably between 50 bars and 55 bars.

[0040] As soon as the mold is closed, a volume of the components of the bandage penetrates the grooves and forms a plug, at the same time the injection of pressurized fluid begins to contain the penetration of the components of the bandage into said grooves. The progressive control of the increase in pressure of the pressurized fluid associated with the plug effect prevents a leak of pressurized fluid between the molding inner part and the Raw. This control also allows time the bandage components to penetrate the reinforcements and compact, this prevents the appearance of blisters at the press outlet.

[0041] Advantageously, the passages for stay cables are formed by grooves, preferably blind, which are hollowed out from the receiving surface in the thickness of the reserved volume so as to present a continuous opening along the profile of the receiving surface, from the top zone to the lateral zone concerned.

[0042] According to one embodiment, the core comprises an assembly of several single-piece angular sectors arranged in azimuth around the central axis of the tool, according to an alternation of sectors called "keys", preferably designed to be accessible by radially internal approach and to be removed first during disassembly of the core, and of sectors called "vaults", supported and locked in position by the keys, and preferably designed to become maneuverable after they have been released by the removal of the keys. The vaults form sectors complementary to the keys.

[0043] Such an arrangement in single-piece sectors will facilitate demolding, and will also allow the stays to be passed locally on the radially external side of the core, onto the receiving surface which will receive the components of the wall of the bandage, which will allow the corresponding portion of the stays to be easily integrated into the wall and therefore ensure the anchoring of said stays in the top of the bandage.

[0044] Preferably, each key or key segment and each vault or vault segment comprises its own pressurized fluid supply circuit. Thus, a separate injection can be carried out in each key and vault segment.

[0045] For example, each key comprises a plurality of key grooves distributed, preferably equally distributed, in azimuth around the central axis according to an angular repetition pitch, the key grooves being, for example, generated along radial planes containing the central axis.

[0046] Preferably, each key comprises a housing extending radially from a radially internal surface radially outwards, without opening onto the receiving surface, the fluid supply circuit comprises two main key conduits originating in the corresponding supply housing and extending axially respectively towards the lateral zones and two secondary key conduits extending circumferentially from the end of each main conduit in the corresponding key, the secondary key conduits of the corresponding key connecting the key grooves made in the corresponding key.

[0047] For example, each vault comprises a plurality of vault grooves distributed, preferably equally distributed, around the central axis at an angle of inclination forming a non-zero angle relative to a radial axis.

[0048] For example, the vault grooves are generated along planes inclined relative to the radial planes containing the central axis.

[0049] Preferably, each vault comprises a housing extending radially from a radially internal surface radially outwards, without opening onto the receiving surface, the fluid supply circuit comprises two main vault conduits originating in the corresponding supply housing and extending axially respectively towards the lateral zones and two secondary vault conduits extending circumferentially from the end of each main conduit in the corresponding vault, the secondary vault conduits of the corresponding vault connecting the vault grooves made in the corresponding vault.

[0050] Advantageously, the vault grooves are not parallel to the key grooves.

[0051] Such an arrangement makes it possible to improve the extraction of the core from the bandage after the cooking step.

[0052] Generally, the grooves are arranged at a variable angle of inclination which depends on the size of the core.

[0053] Alternatively, it could be provided that the grooves are all identical and inclined in the same direction.

[0054] The term “groove” means the assembly comprising the key grooves and the vault grooves.

[0055] According to one embodiment, each key comprises two opposite lateral faces forming joint planes of said key with the two vaults adjacent to said key, said lateral faces being inclined according to two slopes forming a V or chevron relative to each other and relative to the sagittal meridian plane of the key in question.

[0056] Alternatively, said lateral faces may be parallel to each other and to the sagittal meridian plane, as described in patent FR 3 120 814 - A1.

[0057] According to one embodiment, each vault comprises two opposite lateral faces forming joint planes of said vault with the two keys adjacent to said vault, said lateral faces being inclined according to two slopes forming an inverted V or inverted chevron relative to each other and relative to the sagittal meridian plane of the vault considered.

[0058] Advantageously, each keystone and vault is delimited by a lateral flank each having, in section in a radial plane, a curved, convex external profile, which ensures a curved transition between the top zone and the corresponding lateral zone of the receiving surface, and the curvature of which matches the curvature of the hollow of the cavity of the bandage, and more particularly the curvature of the internal surface of the wall of the bandage at the transition between the top and the flank, as well as in the zones where the wall draws the axially most external points of the flanks.

[0059] In this way, the lateral flanks of the keystones and vaults each form a lobe which can occupy, temporarily fill and therefore conform, the hollow of the cavity of the bandage, during the manufacture of said bandage.

[0060] It will be noted in this respect that, due to the concavity of the cavity and the axial tightening formed by the beads relative to the flanks, said beads are located radially in line with the lateral flanks of the keystones and vaults.

[0061] Preferably, the fluid used is chosen from the group comprising nitrogen, helium, argon, carbon dioxide, any non-heat-transferring inert gas. Alternatively, the fluid used could be water. However, a gas has the advantage of not leaving a deposit.

[0062] According to a second aspect, the invention relates to a method of manufacturing by molding an object comprising a wall having an internal surface which delimits a cavity, the tooling comprising a receiving surface having a shape conjugated to the internal surface of the wall of the object and comprising a plurality of passages which extend under the receiving surface, and which open onto said receiving surface.

[0063] The object being intended to be molded on the receiving surface of the tooling.

[0064] The tooling includes an anti-penetration system configured to control the creep of the material constituting the object in the passages, the anti-penetration system comprising a circuit for supplying a fluid under pressure into the passages and a system for injecting said fluid under pressure during a cooking step of the object.

[0065] Said method comprises: - a preparation step, during which tools are prepared as described previously; - a filling step during which the constituent materials of the object are deposited on the receiving surface of the tool, in order to construct the wall of the object, - a cooking step; and - a step of unmolding the object.

[0066] During the cooking step, the method comprises a step of supporting the pressure increase, during which a fluid under pressure is injected into the tool in order to temporarily fill, at least during the cooking step (S5), the volume of each passage.

[0067] According to a particular embodiment of the invention, the object is a toroidal bandage of a tire comprising a crown intended to form a tread, a first annular bead and a second annular bead designed to allow the bandage to be attached to a mounting support such as a rim, as well as a first sidewall and a second sidewall which connect the crown respectively to the first bead and to the second bead, the crown, the first and second sidewalls and the first and second beads forming as a whole a wall having a concave internal surface which delimits a cavity of the bandage.

[0068] Said bandage comprising reinforcing elements, called "stays", which each extend into the cavity of the bandage by connecting a top anchoring point located in the top of the bandage to a lateral anchoring point located in one of the sides or beads of the bandage.

[0069] Said method comprises: - a preparation step, during which tools are prepared as described previously; - a pre-filling step during which anchoring structures are placed on the lateral zones and on the top zone of the receiving surface of the core, opposite the anchoring points provided for attaching the reinforcements to the wall of the bandage, which are designed to collect the ends of the reinforcements which emerge from the passages of the core and to adhere to the constituent components of the flanks or the beads, respectively to the constituent components of the crown, by sandwiching said ends of the reinforcements between the anchoring structures and said components, in order to ensure the fixing of the reinforcements to the anchoring points provided; - a reinforcement installation step, during which a reinforcement wire, intended to form a stay, is passed through each passage of the core, preferably using a continuous reinforcement wire which is arranged in a serpentine fashion through the successive passages by making said continuous reinforcement wire go back and forth in one piece from one lateral zone of the core to the other lateral zone via the top zone, - a filling step during which the components constituting the crown, the sides and the beads of the bandage are deposited on the receiving surface, in order to construct the wall of the bandage, preferably by winding said components onto the rotating core, in order to construct the wall of the bandage, - a cooking step; and - a demolding step during which the core of the bandage is removed, leaving the reinforcements in place in the cavity of said bandage.

[0070] During the pressure build-up support step, a pressurized fluid is injected into the core in order to temporarily fill, at least during the baking step, the volume of each passage which is left free between the reinforcing element engaged in said passage.

[0071] Thus, during the pressure build-up support step, the anti-penetration system is implemented which, during the baking step, cooperates with the core to prevent penetration of the constituent components of the crown, sides or beads of the bandage into the grooves of the core in which the reinforcements are engaged.

[0072] During the curing step, the core and the raw bandage carried by said core are placed in a curing mold, in order to vulcanize the components of the rubber-based bandage. For this purpose, the temperature of the mold, and more particularly of the bandage, will preferably be brought to a value between 120°C and 200°C.

[0073] It is the gas pressure which, by blocking the components constituting the bandage outside the grooves, effectively gives the molding pressure.

[0074] Without injection of pressurized gas during the curing step, the components of the raw bandage will penetrate into the grooves and the molding pressure could not reach the necessary molding pressure of between 50 bars and 60 bars, preferably equal to 55 bars.

[0075] Such a solution does not require interrupting the manufacturing process to install a device for mechanically closing the grooves. There is also no material to remove after dismantling the core.

[0076] According to one embodiment, the core comprises an assembly of several single-piece angular sectors arranged in azimuth around a central axis of the tool, according to an alternation of sectors called "keys", and sectors called "vaults", supported and locked in position by the keys, the vaults forming sectors complementary to the keys and each key or key segment and each vault or vault segment comprising its own circuit for supplying the pressurized fluid.

[0077] More particularly, during said preparation step, the key and vault segments will be assembled to form the core.

[0078] During the pressure build-up support step, the pressurized fluid is injected into the supply circuit of each key and each vault.

[0079] Thus, a separate injection can be carried out in each keystone and vault segment.

[0080] Advantageously, the fluid is injected at a progressive pressure increasing linearly until reaching a pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, linearly to reach a first pressure of between 20 bars and 35 bars for a first duration of between 50s and 100s, for example equal to 60s, then following a second slope for a second duration of between 120s and 200s, for example equal to 150s, to reach a molding pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, preferably between 50 bars and 55 bars.

[0081] For example, the duration of the cooking step is between 500s and 800s at a temperature between 150°C and 200°C, preferably 170°C.

[0082] Advantageously, the injection of the pressurized gas carried out in the pressure build-up support step starts directly or after the mold has closed.

[0083] The injection of pressurized fluid at a low pressure initially has the effect of allowing a small quantity of components forming the bandage to penetrate into the grooves. to ensure a seal between the core and the green bandage, allowing the pressurized fluid to be contained in the grooves without leakage into the bandage. Brief description of the drawings

[0084] 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:

[0085] [Fig.lA] illustrates a sectional view in a radial plane of an example of a braced bandage produced according to the invention;

[0086] [Fig.lB] illustrates a partial perspective view of the guyed bandage of [Fig.lA];

[0087] [Fig.2A], [Fig.2B] illustrate, according to respectively exploded and assembled perspective views, an annular subassembly forming a core of a tool according to the invention, said subassembly being angularly subdivided into sectors, which alternately form sectors called “vaults” and sectors called “keys” designed to lock the vaults in position; said sectors being each intended to receive the constituent components of a bandage sidewall and which contain passages for the stays;

[0088] [Fig.3] is a detail view in section in a radial plane of the tooling illustrated in [Fig.2B];

[0089] [Fig.4A], [Fig.4B] illustrate in detail in perspective, respectively full and in section of a key of the core of the tool of figures 2A and 2B;

[0090] [Fig.5A], [Fig.5B] illustrate in detail in perspective, respectively full and in section of a vault of the core of the tool of figures 2A and 2B;

[0091] [Fig.6] illustrates, according to a detailed sectional view in a meridian plane passing through the middle of the grooves, of the core of the tooling of figures 2A and 2B, the installation of the stays within said core, before the production of the wall of the bandage;

[0092] [Fig.7] represents a cooking step during the tire manufacturing process;

[0093] [Fig. 8] represents a flowchart of a process for manufacturing a strut tire with the tooling of Figures 2A to 6;

[0094] [Fig.9] represents the pressure rise curve of the fluid to be injected during the pressure rise support step; and

[0095] [Fig. 10] illustrates an example of construction of the keystones and vaults of the tooling of figures 2A and 2B.

[0096] Detailed description of at least one embodiment

[0097] Figures 2A, 2B and 3 illustrate a tool 1 intended for the manufacture of a toroidal bandage 100, as illustrated in Figures 1A and 1B. More generally, the tool 1 could be intended for the manufacture of any object intended to be molded on a molding surface of the tool comprising a plurality of passages or orifices.

[0098] Such a bandage 100 preferably constitutes a pneumatic bandage intended to equip a wheel of a vehicle, to ensure the connection of said vehicle with the ground.

[0099] The bandage 100 has a shape of revolution around an axis called the “central axis” XI-XI which corresponds substantially, in practice, to the axis of rotation of the wheel.

[0100] This central axis Xl-Xl defines three directions conventionally used by those skilled in the art: an axial direction, a radial direction and a circumferential direction.

[0101] By “axial direction” is meant a direction collinear with the central axis Xl-Xl of the tire 100, that is to say collinear with the axis of rotation of the tire 100.

[0102] By "radial direction" is meant a direction which extends along a radius of the tire 100, that is to say any direction which is secant and perpendicular to the central axis Xl-Xl.

[0103] By "circumferential direction" is meant a direction which is perpendicular to both the axial direction and to a radius of the tire 100, and which corresponds, in a plane normal to the central axis Xl-Xl, to the tangent to a circle whose center is on the axis of rotation of the tire 100.

[0104] The bandage 100 comprises, in a manner known per se, a crown 101 intended to form a tread, a first annular bead 102 and a second annular bead 103 designed to allow the bandage 100 to be attached to a mounting support, such as a rim.

[0105] The bandage 100 further comprises a first flank 104 and a second flank 105 which connect the crown 101 respectively to the first bead 102 and to the second bead 103.

[0106] By simple convention, it can be considered that, in a meridian plane P_Mer, the limit between the apex 101 and the flank 104, 105 considered corresponds to the axially outermost point of the external surface of the bandage 100 for which the angle between the tangent to the external surface of the bandage 100 and a straight line parallel to the central axis Xl-Xl is equal to 30°.

[0107] By "meridian plane" P_Mer, or radial plane, we mean a plane parallel to, and containing, the central axis XI-XI. Such a meridian plane is normal to the circumferential direction.

[0108] By “equatorial plane” P_Eq, we mean a plane normal to the central axis Xl-Xl and which passes through the radially outermost point of the tire, which is, preferably, located axially midway between the axially outermost points of the tire 100.

[0109] Said equatorial plane P_Eq therefore axially divides the bandage 100 into two toroidal halves, preferably substantially equal, called, by analogy with the terrestrial globe, “hemispheres”.

[0110] The crown 101, the first and second flanks 104, 105 and the first and second beads 102, 103 form as a whole a wall 106 having a concave internal surface 106_in which delimits an internal cavity 107 of the bandage 100.

[0111] In practice, the internal cavity 107 of the tire 100 is toroidal, and advantageously forms the inflation cavity of the tire 100, which is intended to receive a pressurized fluid, such as air, to support the crown 101 of the pneumatic tire 100 relative to the rim.

[0112] Preferably, as can be seen in Figures 1A and 1B, each bead 102, 103 is located axially set back from the axially most protruding position of the corresponding flank 104, 105, i.e. the bead 102, 103 is closer to the equatorial plane P_Eq than the flank 104, 105 to which said bead is connected. Thus, the flank 104, 105 forms, between the apex 101 and the corresponding bead 102, 103, in section in the meridian plane P_Mer, a profile which is generally curved towards the outside and the end of which forming the bead 102, 103 is axially re-entrant, so that the cavity 107 has, in section in said meridian plane, substantially a Q (capital Omega) shape.

[0113] The bandage 100 comprises reinforcing elements 108, called “stays”, designed to permanently integrate the structure of the bandage 100 and extend into the internal cavity 107 of said bandage by connecting a top anchoring point 109 located at the top 101 of the bandage 100 to a lateral anchoring point 110 located in one of the flanks 104, 105 or the beads 102, 103 of the bandage 100.

[0114] As illustrated in Figures 1A, 1B, the top 109 and lateral 110 anchoring points of each stay 108 are located at the same azimuth around the central axis Xl-Xl of the bandage 100, so that the stays 108 extend along radial planes containing the central axis Xl-Xl of the bandage 100.

[0115] The shrouds 108 may represent different configurations, in particular a variety of orientations, without departing from the scope of the invention.

[0116] Each stay 108 is preferably contained in a single hemisphere, in that no stay 108 crosses the equatorial plane P_Eq inside the internal cavity 107 of the bandage 100.

[0117] Each stay 108 is intended to work in traction and therefore to connect the top anchoring point 109 to the corresponding lateral anchoring point 110 along a straight line segment, that is to say by geometrically forming a taut or quasi-taut cord, under the arc which is formed by the internal surface 106_in of the wall 106 between the top anchoring point 109 and the lateral anchoring point 110 in the bandage 100 at rest, and this so that the stay opposes the mutual distancing of said anchoring points 109, 110 relative to each other, and thus increases the lateral rigidity of the bandage 100.

[0118] The stays 108 are, as illustrated, distributed in azimuth around the central axis XI-XI, here, uniformly, according to a constant angular repetition pitch, for example between 0.5° and 5°.

[0119] Alternatively, another distribution of the stays 108 could be provided, as will be described with reference to the tool 1.

[0120] According to the invention, the tool 1 comprises a toroidal core 10 having, around its central axis X2-X2, an external surface 10_out, called the receiving surface, which has a shape conjugated to the internal surface 106_in of the wall 106 of the bandage 100.

[0121] The external surface 10 comprises a radially external top zone 11 intended to receive components constituting the crown 101 of the tire 100, and, on either side axially of said top zone 11, a first lateral zone 12 folded towards the central axis X2-X2 of the core 10 and intended to receive components constituting the first flank 104 and the first bead 102, as well as a second lateral zone 13 intended to receive components constituting the second flank 105 and the second bead 103.

[0122] In this way, the core 10 materializes a volume, called “reserved”, which is delimited externally by the receiving surface 10_out and which corresponds to the internal cavity 107 of the bandage 100.

[0123] The core 10 can thus occupy, and therefore temporarily reserve, during the manufacture of the bandage 100, the volume whose shape and dimensions correspond to the internal cavity 107, a volume which will become the internal cavity 107 of the bandage when the core 10 has been removed from said bandage 100, during the demolding operation which will end the manufacturing cycle of the bandage 100.

[0124] It will be noted that, in practice, the central axis X2-X2 of the core 10, around which said core 10 forms a ring, will merge with the central axis Xl-Xl of the bandage 100 manufactured on the core 10. For convenience of description, one or the other can therefore be designated indifferently by the expression “central axis”.

[0125] As illustrated, the core 10 comprises a plurality of passages 15 which extend inside the reserve volume, under the receiving surface 10_out, and which open onto said receiving surface 10_out so that each of said passages 15 connects the top zone 11 of the receiving surface 10_out to one of the first and second lateral zones 12, 13 so that the core 10 can receive, inside said passages 15, the reinforcing elements 108 of the bandage 100.

[0126] The passages 15 thus correspond to empty spaces which are provided in the core 10, inside the reserve volume, to be able to accommodate the stays 108, and thus allow each stay 108 to cross the receiving surface 10_out, a first time to enter the reserved volume, to be able to accommodate the stays 108, and thus allow each stay 108 to cross the receiving surface 10_out, a first time to enter the reserved volume, here through the lateral zone 12, 13, and a second time to exit the reserved volume, here in the summit zone 11, or vice versa.

[0127] Advantageously, whatever the configuration of the stays 108, the core 10 according to the invention makes it possible to install said stays 108 in the volume reserved by the core 10, and therefore in the space which will become the internal cavity 107 of the bandage 100, prior to the constitution of the bandage 100, according to a distribution and an arrangement which will correspond substantially, or even exactly, to the distribution and the arrangement which said stays 108 will have within the finished bandage 100, ready to be mounted on the rim, since the stays 108 remain in place inside the internal cavity 107, in the desired position, and integral with the bandage 100, when the core 10 is removed.

[0128] Thanks to the use of a core 10 according to the invention, it is therefore ensured that the bandage 100 will have a well-controlled and reproducible configuration from one bandage 100 to another.

[0129] Furthermore, since the stays 108 are thus sheltered in the passages 15 of the core 10 during the installation of the components constituting the wall 106 of the bandage 100, there is no risk of accidentally moving, tearing off or damaging said stays 108 during the manufacturing process of the wall 106 of the bandage 100.

[0130] In a particularly preferential manner, it will be possible to choose to arrange the passages 15 according to open demouldable shapes, allowing the production of a permanent, reusable core 10, which can be extracted from the bandage 100, after manufacturing said bandage 100, without damage to the stays 108, then reused to manufacture the next bandage.

[0131] In this respect, the passages 15 for shrouds 108 will preferably be formed by grooves hollowed out from the receiving surface 10_out in the thickness of the reserved volume so as to present a continuous opening along the profile of the surface. reception 10_out, from the top zone 11 to the relevant lateral zone 12, 13.

[0132] Advantageously, since each groove 15 creates, at the receiving surface 10_out, a slot-like opening which extends over the entire length of the receiving surface 10_out going from the lateral anchoring point 110 of the stay 108 concerned to the top anchoring point 109 of said stay 108, it is possible to engage the stay 108 in the passage 15 before the installation of the constituent components of the wall 106 of the bandage 100, simply by sliding said stay 108 into the corresponding groove 15, from the outside of the core 10, so that the stay 108 passes through the receiving surface 10_out to sink into the reserved volume, in the direction of the central axis X2-X2 of the core 10.

[0133] Advantageously, after the components constituting the wall 106 of the bandage 100 have been placed on the receiving surface 10_out, so that the wall 106 will cover the grooves 15, it will be possible to extract the core 10 from the inside of the bandage 100, by gradually removing the stays 108, now fixed to the wall 106 and therefore integrated into the bandage 100, through the openings of the grooves 15 of the core 10 from which it is released, and thus leaving the stays 108 in their final place in the internal cavity 107 of the bandage 100.

[0134] For convenience of description, and in order not to overload the figures, the same reference “15” will designate the passages for stays 108 and the grooves which constitute a specific preferred form of said passages for stays 108.

[0135] Preferably, the grooves 15 are blind, that is to say that the grooves 15 have a solid bottom 19, visible in [Fig.3], located under the receiving surface 10_out, in the reserved volume and which extends from a first mouth of the groove 15, which opens onto the lateral zone 12, 13 of said receiving surface 10_out, to a second mouth of the groove 15, which opens onto the top zone 11 of said receiving surface 10_out.

[0136] Thus, when the stay 108 is in place in the corresponding groove 15, said stay 108 is located radially, and more particularly is contained radially, relative to the central axis X2-X2 of the core 10, between the bottom and the opening of the groove 15 located on the receiving surface 10_out.

[0137] The stay 108 can either be detached radially above the bottom of the groove 15, that is to say located at a non-zero radial distance from said bottom, beyond the bottom 19 relative to the central axis X2-X2, or rest on said bottom 19, which will then advantageously serve as a guide and support for said stay 108 during the manufacture of the bandage 100.

[0138] Preferably, the depth of the grooves 15, relative to the receiving surface 10_out, and therefore more particularly the distance which separates the bottom 19 from the groove 15 of the receiving surface 10_out, is sufficient so that each of said grooves 15 can allow the stay 108 to follow, within said groove 15, a path which directly connects the lateral anchoring point 110 to the summit anchoring point 109 along a straight line segment.

[0139] Thus, the stay 108 will be able to adopt its functional configuration within the groove 15, without interfering with or being deformed or deflected by said groove 15, functional configuration according to which said stay 108 forms a rope which connects by the shortest path the ends of the arc drawn by the wall 106 of the bandage 100 between the lateral anchoring point 110 and the top anchoring point 109, so that said stay 108 will be able, once the bandage 100 is released from the core 10, to work effectively in traction, in the manner of a tie rod, between the lateral anchoring point 110 and the top anchoring point 109.

[0140] According to a preferred characteristic which can be applied whatever the nature and shape of the passages 15 for stays 108, but which is more particularly interesting in cases where said passages 15 for stays are formed by grooves 15, the core 10 comprises, as is notably visible in FIGS. 2A and 2B, an assembly of several single-piece angular sectors arranged in azimuth around the central axis X2-X2, according to an alternation of sectors called "keys" 20, designed to be accessible by radially internal approach and to be removed first during disassembly of the core 10, and of sectors called "vaults" 21, supported and locked in position by the keys 20, and designed to become maneuverable after they have been released by the removal of the keys 20.

[0141] The number of keys 20, equal to the number of vaults 21, will be chosen to be sufficiently high to allow easy splitting and disassembly by centripetal radial extraction of said sectors 20, 21 constituting the core 20, and nevertheless sufficiently moderate so as not to multiply the sectors unnecessarily, and therefore to simplify the assembly of the core 20. As such, the number of keys 20, and therefore the number of vaults 21, will preferably be between 4 and 6, and more preferably equal to 5, as is the case in FIGS. 2A and 2B.

[0142] For the sake of standardization and for ease of assembly, all the keys 20 will preferably be identical to each other, and therefore interchangeable. Similarly, all the vaults 21 will preferably be identical to each other, and therefore interchangeable.

[0143] Preferably, the lateral faces 20a, 20b which delimit each key 20 and which form the joint planes of said key 20 with the two vaults 21 adjacent to said key 20, are here inclined according to two slopes forming a V or chevron relative to each other and relative to the sagittal meridian plane of the key 20 considered.

[0144] Alternatively, said lateral faces may be parallel to each other and to the sagittal meridian plane, as described in patent FR 3 120 814 - A1.

[0145] The vaults 21 will of course form sectors complementary to the keys 20, and will be locked in position by said keys 20 within the core 20.

[0146] The lateral faces 21a, 21b which delimit each vault 21 and which form the joint planes of said vault 21 with the two keys 20 adjacent to said vault 21, will be inclined according to two slopes forming an inverted V or inverted chevron relative to each other and relative to the sagittal meridian plane of the vault 21 considered.

[0147] By analogy with the architectural field, the keys 20, moreover positioned and maintained by a common annular support 22, will therefore prevent the collapse of the vaults 21, and more generally of the arch formed by the succession of said keys 20 and vaults 21. This support provided by the keys 20 will be all the more robust and stable as the clearance angle of the lateral faces of the keys 20 is high.

[0148] To dismantle the core 20 and extract it from the bandage 100 during the demolding operation, one will therefore begin by extracting the keys 20, according to a centripetal radial extraction movement, followed by an axial release movement, which will have the effect of releasing the vaults 21, which will then be extracted in turn by a centripetal radial extraction movement, then an axial release movement.

[0149] Alternatively, it could be provided that the core 10 does not comprise a plurality of single-piece angular sectors but a central crown on which left and right ears are mounted, as described in patent FR 3 120 814 - AL

[0150] Advantageously, such an arrangement in single-piece sectors will facilitate demolding, and will also make it possible to locally pass the stays 108 on the radially external side of the core 10, onto the receiving surface 10_out which will receive the components of the wall 106 of the bandage, which will make it possible to easily integrate the corresponding portion of the stays 108 into the wall 106 and therefore to ensure the anchoring of said stays in the top 101 of the bandage 100.

[0151] Preferably, the top portion of the core 10 forms a right cylinder, with a circular base, centered on the central axis X2-X2.

[0152] Furthermore, preferably, the equatorial plane P_EQ is contained in the axial range covered by the central portion of the summit zone 11 of the core 10, and more particularly is located in the middle of said axial range, so as to subdivide the summit zone 11 into two parts which are equal, or even symmetrical to each other, with respect to said equatorial plane PEQ.

[0153] Each key 20 and vault 21 is delimited by a lateral flank 20c, 20d, 21c, 21d each having, in section in a radial plane, a curved, convex external profile, which ensures a curved transition between the summit zone 11 and the corresponding lateral zone 12, 13 of the receiving surface 10_out, and the curvature of which matches the curvature of the hollow of the cavity 107 of the bandage 100, and more particularly the curvature of the internal surface 106_in of the wall 106 of the bandage at the transition between the top 101 and the flank 104, 105, as well as in the areas where the wall 106 draws the axially outermost points of the flanks 104, 105.

[0154] In this way, the lateral flanks 20c, 20d, 21c, 21d of the keys 20 and vaults 21 each form a lobe which can occupy, temporarily fill and therefore conform, the hollow of the cavity 107 of the bandage 100, during the manufacture of said bandage 100.

[0155] It will be noted in this respect that, due to the concavity of the cavity 107 and the axial tightening formed by the beads 102, 103 relative to the flanks 104, 105, said beads 102, 103 are located radially in line with the lateral flanks 20c, 20d, 21c, 21d of the keys 20 and vaults 21.

[0156] The angular segments 20, 21 forming the core 10 will preferably be reusable from one manufacturing cycle to another, and for this purpose made of a durable material, such as an aluminum alloy.

[0157] For this purpose, an arrangement of the tool 1 will be provided which will be adapted to the dismantling of the core 10, and more particularly to the dismantling of the angular segments 20, 21, from the inside of the bandage 100.

[0158] To prevent the walls of the grooves 15 from rubbing excessively against the stays 108 or from tearing the stays during the extraction of the angular sectors 20, 21, and more particularly during the extraction of the keys 20, said sectors 20 will each cover a relatively smaller angular sector than the vault sectors 21 around the central axis X2-X2.

[0159] As a non-limiting example, the construction of the key sectors 20 and vaults 21 of the tool 1 can be carried out with reference to [Fig. 10].

[0160] From a circle with center C, with a diameter equal to 159mm for example, two tangents T1 and T2 are drawn to the circle, in bold dotted lines, to form the lateral contours of the key, here in bold. The two tangents T1, T2 form between them an angle al between 1° and 10°, preferably equal to 3°.

[0161] The two lateral contours of the key comprise, at their radially inner end, a chamfer forming an angle of between 3° and 10° with the associated tangent T1, T2. Such a chamfer makes it possible to disassemble the key segments first.

[0162] To construct the vault segment 21, we draw two tangents T3, T4 to the circle, each passing through the chamfer of the key.

[0163] The radially outer surface of the arch segment forms an angle a2 between 50° and 75°, preferably equal to 75°.

[0164] It is also possible, according to a preferred characteristic, to provide a core 10 within which the sectors 20, 21 contain heating elements, such as electrical heating resistors, to ensure a rapid and uniform rise in temperature of the receiving surface 10_out during the baking operation of the bandage 100.

[0165] As illustrated, each key segment 20 comprises a plurality of grooves 15a distributed, preferably equally distributed, in azimuth around the central axis X2-X2 according to the desired angular repetition pitch for the stays 108. The grooves 15a of the key segments 20 are here radial.

[0166] The key grooves 15a are generated along radial planes containing the central axis X2-X2, as is the case in FIGS. 3A and 3B so as to allow the installation within the bandage 100 of stays 108 extending along said radial planes, as is the case with the bandage of FIGS. 1A and 1B.

[0167] Alternatively, it could also be provided that the key grooves 15a intersect so as to form a grid on the receiving surface 10_out, in order to allow the installation of crossed stays 108 within the bandage 10.

[0168] As illustrated, each arch segment 21 comprises a plurality of grooves 15b distributed, preferably equally distributed, around the central axis X2-X2 at an angle of inclination forming a non-zero angle relative to the radial axis.

[0169] The arch grooves 15b are generated along planes inclined relative to the radial planes containing the central axis X2-X2, as is the case in FIGS. 3A and 3B so as to allow the installation within the bandage 100 of stays 108 extending along said planes inclined relative to the radial planes.

[0170] The grooves 15b of the arch segments 21 are therefore not parallel to the grooves 15a of the key segments 20. Such an arrangement makes it possible to improve the extraction of the core 10 from the bandage 100 after the cooking step.

[0171] Generally, the grooves 15a, 15b are arranged according to a variable angle of inclination which depends on the dimension of the core 10.

[0172] Alternatively, it could be provided that the grooves 15a, 15b are all identical and inclined in the same direction.

[0173] The groove 15 means the assembly comprising the key grooves 15a and the vault grooves 15b.

[0174] The width of the groove 15, i.e. the dimension considered in the circumferential direction, will preferably be chosen as a function of a compromise between i) taking into account the width (diameter) of the stay 108, the need to ensure functional clearance between the stay 108 and the side walls which delimit the groove 15, functional clearance which is sufficient to allow the insertion of the stay 108 into the groove 15, then the extraction of the core 10 from the bandage 100, and therefore the extraction of the stay 108 from the groove 15 without jamming and without damage to the stay 108, and ii) maintaining an opening and a groove width which is sufficiently narrow so as not to weaken the core 10 and to ensure good quality support for the components of the bandage 100 placed on the receiving surface 10_out, and limit if possible penetration, and therefore deformation or fining, of the materials constituting said components of the bandage 100 in the grooves 15.

[0175] In this respect, the width of the groove 15, and in particular the width of the opening of the groove 15 at the receiving surface 10_out, will preferably be between 1.01 times and 1.5 times the corresponding dimension of the cross-section of said stay 108, and more preferably the largest dimension of the cross-section of the stay. In practice, if the stay is formed by a wire, single-strand or multi-strand, of substantially circular cross-section, then the considered dimension of the cross-section of the stay will be the diameter of the circular cross-section of the wire.

[0176] Preferably, for the same reasons, and in particular if we are considering stays 108 whose section has a diameter of between 0.25 mm and 2 mm, for example of the order of 1 mm, we will choose a groove width 15 of between 0.1 mm and 3 mm, in particular at the level of the opening at the receiving surface 10_out, preferably between 0.3 mm and 2.2 mm, and for example between 1 mm and 1.8 mm.

[0177] Preferably, all the grooves 15 of the same hemisphere of the core 10, and more preferably all the grooves 15 of the core 10, will have an identical width.

[0178] Furthermore, according to a preferred characteristic which may constitute an invention in its own right, and which may apply to any variant described in the above, in particular when the passages 15 for stays 108 are formed by grooves 15, the tooling 1 may comprise an anti-penetration system 30 which cooperates with the core 10 to prevent penetration of the constituent components of the crown 101, the sides 104, 105 or the beads 102, 103 of the bandage 100 into the passages 15 of the core 10 in which the stays 108 are engaged.

[0179] More particularly, the anti-penetration system 30 prevents the materials, and in particular the rubber-based compositions, present in the components of the tire 100 from penetrating into the grooves 15 by fining, in order to prevent the formation of rubber burrs which would cause the stays 108 to stick to the walls of the grooves 15, and which would therefore create a risk of the stays 108 being torn off at the time of extraction of the angular sectors 20, 21 from the core 10.

[0180] The anti-penetration system 30 comprises a housing 31, 32 made respectively in each key segment 20 and each vault segment 21.

[0181] Each housing 31, 32 extends radially in each corresponding angular segment 20, 21 in the equatorial plane P_EQ from a radially internal surface 20e, 21e radially outwards, without opening onto the receiving surface 10_ out.

[0182] The anti-penetration system 60 further comprises a circuit 33, 34 for supplying a fluid, each associated with an angular segment of key 20 and vault 21.

[0183] Each fluid supply circuit 33, 34 comprises two main conduits 35, 36; 37, 38 originating in the corresponding supply housing 31, 32 and extending axially respectively towards the lateral zones 12, 13.

[0184] The main conduits 35, 36; 37, 38 successively comprise a first radial part 35a, 36a; 37a, 38a connected to the corresponding supply housing 31, 32, a bent part 35b, 36b; 37b, 38b and a second part 35c, 36c; 37c, 38c inclined obliquely relative to the axial axis parallel to the central axis X2-X2 at an angle between 0° and -10°, for example equal to -5°.

[0185] The anti-penetration system 30 further comprises two secondary key conduits 39, one of which is visible in [Fig.5B], extending circumferentially from the end of each main conduit 35, 36 in the key segment 20 and two secondary vault conduits 40, one of which is visible in FIG. 6B, extending circumferentially from the end of each main conduit 37, 38 in the vault segment 21.

[0186] The secondary key conduits 39 of the key segments 20 connect the grooves 15a made in the key segments 20 and the secondary vault conduits 40 connect the grooves 15b made in the vault segments 21.

[0187] The main key conduits 35, 36 and the secondary key conduits 39 together form an internal key circuit independent of each key segment 20 allowing a fluid to be brought inside the grooves 15a in each key segment 20.

[0188] The main vault conduits 37, 38 and the secondary vault conduits 40 together form an internal vault circuit independent of each vault segment 21 making it possible to bring a fluid inside the grooves 15b in each vault segment 21.

[0189] Thus, a separate injection can be carried out in each keystone and vault segment.

[0190] The anti-penetration system 20 comprises an injection system (not shown) for a fluid to fill the gas supply circuits and thus the grooves 15, respectively 15a, 15b, thus substantially closing the interstitial space which remains vacant within the passages 15 after the stays 108 have been put in place in said passages 15.

[0191] The injection under pressure of a fluid into the grooves 15 makes it possible to prevent, or substantially slow down, the penetration into the groove 15 of the materials constituting the components of the tire, and in particular of the mixtures based on unvulcanized rubber.

[0192] The fluid used is chosen from the group comprising nitrogen, helium, argon, carbon dioxide, any non-heat-transferring inert gas. Alternatively, the fluid could be water.

[0193] Of course, the invention also relates to a method S for manufacturing a bandage 100 braced on a core 10.

[0194] Such a method in practice preferably amounts to using a tool 1 as described above.

[0195] Thus, the invention also relates to a method S for manufacturing a toroidal bandage 100 comprising a crown 101 intended to form a tread, a first annular bead 102 and a second annular bead 104 designed to allow the bandage to be attached to a mounting support such as a rim, as well as a first sidewall 104 and a second sidewall 105 which connect the crown 101 respectively to the first bead 102 and to the second bead 103, the crown 101, the first and second sidewalls 104, 105 and the first and second beads 102, 103 forming as a whole a wall 106 having a concave internal surface 106_in which delimits a cavity 107 of the bandage 100, said bandage 100 comprising reinforcing elements 108, called “stays” » 108, which each extend into the cavity 107 of the bandage by connecting a top anchoring point 109 located in the top 101 of the bandage to a lateral anchoring point 110 located in one of the flanks 104,105 or beads 102, 103 of the bandage.

[0196] Said method S, described with reference to [Fig.8], comprises a preparation step (S0), during which a tool 1 according to the invention is prepared.

[0197] More particularly, during said preparation step (S0), the key segments 20 and vaults 21 will be assembled to form the core 10, as illustrated in FIGS. 2A and 2B.

[0198] The method S then comprises a step (S2) of placing stays 108, during which at least one reinforcing wire, intended to form a stay 108, is passed through each passage 15 of the core 10.

[0199] Preferably, a single continuous reinforcing wire, single-strand or multi-strand, is used to form several stays 108, preferably more than 25%, more than 50%, or even the entire number of stays 108 of the bandage 100.

[0200] To do this, the continuous reinforcing wire is preferably arranged in a serpentine fashion through the successive passages 15, here by inserting said reinforcing wire into the grooves 15, under the receiving surface 10_out, and by bringing out said reinforcing wire above the receiving surface 10_out in the top zone 11 and in the lateral zones 12, 13, at the desired anchoring points 109, 110, thereby making said continuous reinforcing wire go and return in one piece from one lateral zone 12 of the core 10 to the other lateral zone 13 via the top zone 11, so as to form undulations, for example of substantially symmetrical amplitude relative to the equatorial plane P_EQ.

[0201] Preferably, following the preparation step (S0), and before the step (S2) of installing stays 108, said method S comprises a pre-filling step (S1) during which, as illustrated in [Fig. 6], anchoring structures 71, 72 are placed on the lateral zones 12, 13 and on the top zone 11 of the receiving surface 10_out of the core 10, opposite the anchoring points 110, 109 provided for attaching the stays 108 to the wall 106 of the bandage, which are designed to collect the ends of the stays 108 which emerge from the passages 15 of the core 10 and to adhere to the constituent components of the flanks 104, 105 or the beads 102, 103, respectively to the components constituting the summit 101, by sandwiching said ends of the stays 108 between the anchoring structures 71, 72 and said components, in order to ensure the fixing of the stays 108 to the anchoring points 110, 109 provided.

[0202] Preferably, the anchoring structures 71, 72 will be formed from unvulcanized rubber-based material, possibly reinforced by means of reinforcing threads or fibers. The anchoring structures 71, 72 may, for example, take the form of reinforcing strips or turns wound on the core 10.

[0203] The anchoring structures 71, 72 being positioned in standby on the receiving face 10_out, outside the grooved portions, at the desired anchoring points 110, 109, the stays 108 will be put in place in the passages 15 by ensuring that the portions of said stays 108 which emerge from the passages 15 come to be positioned over said anchoring structures 71, 72, so that when the components of the wall 106 of the bandage are then placed, said components adhere to the anchoring structures already in place on the core 10, and said anchoring structures 71, 72 therefore integrate the wall 106 of the bandage 100, thus pinching the ends of the stays 108 inside the wall 106, at the anchoring points 110, 109 planned.

[0204] Preferably, it is the loops forming the extremes of the undulations of the continuous reinforcing wire coil, and which therefore correspond to the transition zones between two successive stays belonging to the same hemisphere, which form the portions of the stays 108 which will be captive to the lateral anchoring structures 71 placed on the lateral zones 12, 13, to form the lateral anchoring points 110 of the stays, while the intermediate portions of the continuous reinforcing wire which connect two successive stays 108 belonging to two different hemispheres, emerging from the groove 15 of the first stay in order to travel through the top zone 11 of the receiving surface 10_out and cross the equatorial plane P_EQ then plunge back into the groove 15 of the second stay 108, will be captive to the top anchoring structure 72.

[0205] The method then comprises a filling step (S3) during which the constituent components of the crown 101, the sides 104, 105 and the beads 102, 103 of the bandage are deposited on the receiving surface 10_out, in order to construct the wall 106 of the bandage 100.

[0206] Said components will preferably comprise rubber-based strips or sheets, possibly reinforced by longitudinal reinforcing threads, made of textile, polymer, or metal. Other reinforcing components may be provided, such as composite strips based on fiberglass and resin.

[0207] All or part of said components may preferably be placed by winding on the rotating core 10.

[0208] The method then comprises a cooking step (S5).

[0209] During this, the core 10 and the raw bandage carried by said core 10 are placed in a baking mold M, visible in [Fig.7], in order to vulcanize the components of the rubber-based bandage 100. For this purpose, the temperature of the mold, and more particularly of the bandage, will preferably be brought to a value between 120°C and 200°C.

[0210] During the baking step (S4), the method comprises a step (S5) of supporting the pressure increase, during which an anti-penetration system 30 is implemented which, during the baking step (S4), cooperates with the core 10 to prevent penetration of the constituent components of the crown 101, the sides 104, 105 or the beads 102, 103 of the bandage 100 into the passages 15 of the core 10, here into the grooves 15, in which the stays 108 are engaged.

[0211] During the step (S5) of supporting the pressure increase, a pressurized fluid is injected into the core 10 in order to temporarily fill, at least during the cooking step (S5), the volume of each passage 15 which is left free between the stay 108 engaged in said passage 15 and the opening(s) of said passage 15 which open onto the receiving surface 10_out.

[0212] As illustrated in [Fig.9], the fluid is injected at a progressive pressure increasing until reaching a pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, in a linear manner to reach a first pressure PI of between 20 bars and 35 bars for a first duration T1 of between 50s and 100s, for example equal to 60s, then following a second slope for a second duration T2 of between 120s and 200s, for example equal to 150s, to reach a molding pressure P2 of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, preferably between 50 bars and 55 bars.

[0213] The duration of the cooking step (S5) is between 500s and 800s at a temperature between 150°C and 200°C, preferably 170°C. The increase in pressure of the molding pressure in the mold allows sufficient expansion of the core 10 and the bandage components so that the bandage fills the entire mold cavity.

[0214] Before the end of the second duration, the components of the raw bandage are flowed and after the end of the second duration, the components of the raw bandage are vulcanized, that is to say solid.

[0215] It is the gas pressure which, by blocking the components constituting the bandage outside the grooves 15, effectively gives the molding pressure.

[0216] Without injection of pressurized gas during the curing step (S4), the components of the raw bandage will penetrate into the grooves 15 and the molding pressure could not reach the necessary molding pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, preferably equal to 55 bars.

[0217] The injection of the pressurized gas carried out in the pressure build-up support step (S5) starts after a duration of between 0s and 10s after the start of the curing step (S4). This has the effect of allowing a small quantity of components forming the bandage to penetrate into the grooves 15 in order to ensure a seal between the core 10 and the green bandage, allowing the pressurized fluid to be contained in the grooves 15 without leakage into the bandage 100.

[0218] Such a solution does not require interrupting the manufacturing process to install a device for mechanically closing the grooves. There is also no material to remove after dismantling the core.

[0219] The method then comprises a demolding step (S6) during which the core 10 is released from the bandage 100 while leaving the stays 108 in place in the cavity 107 of said bandage 100.

[0220] If a part of the core 10 is for single use, it can be destroyed by the appropriate process (melting, dissolution, disintegration, shock, sublimation, etc.) to release the cavity 107 and the stays 108.

[0221] If, as is preferably the case, the core 10 is reusable, and therefore formed from a modular assembly of removable parts, the said parts will be dismantled and gradually extracted to release the bandage 100.

[0222] Preferably, the core 10 comprising a plurality of angular segments alternately of keys 20 and arch 21, each containing the passages 15 of stays 16 in the form of grooves 15 which are open on the receiving surface 10 _out, the step (S6) of demolding firstly comprises a first sub-step of removing the key segments 20, then the arch segments 21 from the cavity 107 of the bandage, in order to release the corresponding cavity portion 107 and the stays 108 which are located in said corresponding cavity portion 107, here therefore the stays 108 which occupy the two hemispheres of the bandage 100.

[0223] Whatever the trajectory initially taken for the extraction movement, once the angular sector 20, 21 is freed from the stays 108, the extraction sequence of said angular sector 20, 21 can be completed freely from the inside of the bandage 100, for example by following a radial movement which brings the angular sector 20, 21 concerned closer to the central axis X2-X2, to radially cross the threshold formed by the bead 102, 103, followed by an axial movement which causes said angular sector 20, 21 to completely exit from the envelope which axially delimits the bandage 100.

[0224] Of course, the invention is in no way limited to the embodiment variants described above, the person skilled in the art being able in particular to isolate or freely combine the above-mentioned characteristics, or to substitute equivalents for them.

Claims

Claims

1. Tooling (1) intended for the manufacture by molding of an object (100) comprising a wall (106) having an internal surface (106_in) which delimits a cavity (107), the tooling (1) comprising a receiving surface (10_out) having a shape conjugated to the internal surface (106_in) of the wall (106) of the object (100) and comprising a plurality of passages (15) which extend under the receiving surface (10_out), and which open onto said receiving surface (10_out), the object being intended to be molded on the receiving surface (10_out) of the tooling (1), characterized in that the tooling (1) comprises an anti-penetration system (30) configured to control the fining of the material constituting the object (100) in the passages (15), the anti-penetration system (30) comprising a circuit for supplying a pressurized fluid into the passages (15) and a system for injecting said pressurized fluid during a cooking step of the object (100).

2. Tooling (1) according to claim 1, wherein the object (100) is a toroidal bandage of a tire.

3. Tooling (1) according to claim 2, wherein the toroidal bandage (100) comprises a crown (101) intended to form a tread, a first annular bead (102) and a second annular bead (103) designed to allow the bandage (100) to be attached to a mounting support, as well as a first flank (104) and a second flank (105) which connect the crown (101) respectively to the first bead (102) and to the second bead (103), the crown (101), the first and second flanks (104, 105) and the first and second beads (102, 103) forming as a whole the wall (106) having the concave internal surface (106_in) which delimits the cavity (107) of the bandage (100), said tooling (1) comprising a core (10) toroidal having, around its central axis (X2-X2), the receiving surface (10_out) which has a shape conjugated to the internal surface (106_in) of the wall (106) of the bandage and which comprises for this purpose a summit zone (11),radially external, intended to receive components constituting the top (101) of the bandage (100), and, on either side axially of said top zone (11), a first lateral zone (12) folded towards the central axis (X2-X2) and intended to receive, constituent components of the first sidewall (104) and of the first bead (102) as well as a second lateral zone (13) folded towards the central axis (X2-X2) and intended to receive constituent components of the second sidewall (105) and of the second bead (103), so that the core (10) materializes a volume which is delimited externally by the receiving surface (10_out) and which corresponds to the cavity (107) of the bandage, the core (10) comprising the plurality of passages (15) which extend inside the reserved volume, under the receiving surface (10_out), and which open onto said receiving surface (10_out) so that each of said passages (15) connects the top zone (11) of the receiving surface to one of the first and second lateral zones (12, 13) so that the core (10) can receive, inside said passages (15), reinforcing elements (108),which are designed to permanently integrate the structure of the bandage (100) and each extend into the cavity (107) of the bandage by connecting a top anchoring point (109) located in the crown (101) of the bandage to a lateral anchoring point (110) located in one of the flanks (104, 105) or the beads (102, 103) of the bandage (100), and in which the tooling (1) comprises an anti-penetration system (30) which cooperates with the core (10) to prevent penetration of the constituent components of the crown (101), the flanks (104, 105) or the beads (102, 103) of the bandage into the passages (15) of the core (10) in which the reinforcing elements (108) are engaged, the anti-penetration system (30) comprising a circuit for supplying a pressurized fluid in the passages (15) of the core (10) and a system for injecting said fluid under pressure during a step of cooking the bandage (100).,

4. Tooling according to claim 3, in which the passages (15) for reinforcing elements (108) are formed by grooves (15), preferably blind, which are hollowed out from the receiving surface (10_out) in the thickness of the reserved volume so as to have a continuous opening along the profile of the receiving surface (10_out), from the top zone (11) to the lateral zone (12, 13) concerned.

5. Tooling according to claim 3 or 4, in which the core (10) comprises an assembly of several single-piece angular sectors arranged in azimuth around a central axis (X2-X2) of the tooling (1), according to an alternation of so-called “key” sectors (20), and so-called “vaults” (21), supported and locked in position by the keys (20), the vaults (21) forming sectors complementary to the keys (20).

6. Tooling according to claim 5, in which each key (20) and each vault (21) comprises its own circuit (33, 34) for supplying the pressurized fluid.

7. Tooling according to claim 5 or 6, in which each key (20) comprises a plurality of key grooves (15a) distributed in azimuth around the central axis (X2-X2) according to an angular repetition pitch.

8. Tooling according to claims 6 and 7, wherein each key (20) comprises a housing (31) extending radially from a radially internal surface (20e) radially outwards, without opening onto the receiving surface (10_out), the circuit (33) for supplying a fluid comprises two main key conduits (35, 36) originating in the corresponding supply housing (31) and extending axially respectively towards the lateral zones (12, 13) and two secondary key conduits (39) extending circumferentially from the end of each main conduit (35, 36) in the corresponding key (20), the secondary key conduits (39) of the corresponding key (20) connecting the key grooves (15a) made in the corresponding key (20).

9. Tooling according to any one of claims 6 to 8 in which each arch (21) comprises a plurality of arch grooves (15b) distributed around the central axis (X2-X2) at an angle of inclination forming a non-zero angle relative to a radial axis.

10. Tooling according to claim 9, wherein each vault (21) comprises a housing (32) extending radially from a radially internal surface (21e) radially outwards, without opening onto the receiving surface (10_out), the circuit (34) for supplying a fluid comprises two main vault conduits (37, 38) originating in the corresponding supply housing (32) and extending axially respectively towards the lateral zones (12, 13) and two secondary vault conduits (40) extending circumferentially from the end of each main conduit (37, 38) in the corresponding vault (21), the secondary vault conduits (40) of the corresponding vault (21) connecting the vault grooves (15b) made in the corresponding vault (21).

11. Tooling according to claims 7 and 9 taken in combination with any one of the preceding claims, in which the vault grooves (15b) are not parallel to the key grooves (15a).

12. Tooling according to any one of claims 8 to 11, in which each key (20) comprises two opposite lateral faces (20a, 20b) forming joint planes of said key (20) with the two arches (21) adjacent to said key (20), said lateral faces (20a, 20b) being inclined according to two slopes forming a V relative to each other and relative to the sagittal meridian plane of the key (20) in question.

13. Tooling according to claim 12, in which each vault (21) comprises two opposite lateral faces (21a, 21b) forming joint planes of said vault (21) with the two keys (20) adjacent to said vault (21), said lateral faces (21a, 21b) being inclined according to two slopes forming an inverted V relative to each other and relative to the sagittal meridian plane of the vault (21) considered.

14. Tooling according to any one of claims 5 to 13, in which each key (20) and arch (21) is delimited by a lateral flank (20c, 20d, 21c, 21d) each having, in section in a radial plane, a curved, convex external profile, which ensures a curved transition between the top zone (11) and the corresponding lateral zone (12, 13) of the receiving surface (10_out), and the curvature of which matches the curvature of the hollow of the cavity (107) of the bandage (100).

15. Tooling according to any one of the preceding claims, in which the fluid used is an inert gas chosen from the group comprising nitrogen, helium, argon, carbon dioxide, any non-heat-transferring inert gas.

16. Method (S) for manufacturing by molding an object (100) comprising a wall (106) having an internal surface (106_in) which delimits a cavity (107), the tooling (1) comprising a receiving surface (10_out) having a shape conjugate to the internal surface (106_ in) of the wall (106) of the object (100) and comprising a plurality of passages (15) which extend under the receiving surface (10_ out), and which open onto said receiving surface (10_out), the object being intended to be molded on the receiving surface (10_out) of the tooling (1), characterized in that the tooling (1) comprises a

17. anti-penetration system (30) configured to control the fining of the material constituting the object (100) in the passages (15), the anti-penetration system (30) comprising a circuit for supplying a pressurized fluid into the passages (15) and a system for injecting said pressurized fluid during a step of cooking the object (100). Such tooling makes it possible to mold objects on receiving surfaces or molding surfaces comprising passages or orifices, said method comprising: - a preparation step (S0), during which a tool (1) according to any one of claims 1 to 14 is prepared; - a filling step (S3) during which the constituent materials of the object (100) are deposited on the receiving surface (10_out) of the tool (1), in order to construct the wall (106) of the object (100), - a cooking step (S4); and - a step (S6) of demolding the object (100), characterized in that during the cooking step (S4), the method comprises a step (S5) of supporting the increase in pressure, during which a pressurized fluid is injected into the tool (1) in order to temporarily fill, at least during the cooking step (S5), the volume of each passage (15). Method (S) according to claim 16, wherein the object (100) is a toroidal tire of a tire comprising a crown (101) intended to form a tread, a first annular bead (102) and a second annular bead (103) designed to allow the attachment of the tire (100) to a mounting support, as well as a first sidewall (104) and a second sidewall (104) which connect the crown (101) respectively to the first bead (102) and to the second bead (103), the crown (101), the first and second sidewalls (104, 105) and the first and second beads (102, 103) forming as a whole the wall (106) having the concave internal surface (106_in) which delimits the cavity (107) of the tire, said tire (100) comprising reinforcing elements (108), which each extend into the cavity (107) of the bandage by connecting a top anchoring point (109) located in the top (101) of the bandage to a lateral anchoring point (110) located in one of the flanks (104,105) or beads (102, 103) of the bandage, said method (S) comprising:,

18. - a preparation step (SO), during which a tool (1) according to any one of claims 2 to 14 is prepared; - a pre-filling step (SI) during which anchoring structures (71, 72) are placed on the lateral zones (12, 13) and on the top zone (11) of the receiving surface (10_out) of the core (10), opposite the anchoring points (110, 109) provided for attaching the reinforcing elements (108) to the wall (106) of the tire, which are designed to collect the ends of the reinforcing elements (108) which emerge from the grooves (15) of the core (10) and to adhere to the constituent components of the flanks (104, 105) or the beads (102, 103), respectively to the constituent components of the top (101), by sandwiching said ends of the reinforcements (108) between the anchoring structures (71, 72) and said components, in order to ensure fixing the reinforcements (108) to the anchoring points (110, 109) provided; - a step (S2) of placing the reinforcing elements (108), during which a reinforcing wire, intended to form a reinforcing element (108), is passed through each passage (15) of the core (10), - a filling step (S3) during which the components constituting the top (101), the sides (104, 105) and the beads (102, 103) of the bandage are deposited on the receiving surface (10_out), in order to construct the wall (106) of the bandage (100), - a cooking step (S4); and - a demolding step (S6) during which the core (10) is released from the bandage (100) while leaving the reinforcing elements (108) in place in the cavity (107) of said bandage (100) in which during the step (S5) of supporting the pressure increase, a pressurized fluid is injected into the core (10) in order to temporarily fill, at least during the cooking step (S5), the volume of each passage (15) which is left free between the reinforcing element (108) engaged in said passage (15). Method according to claim 17, in which the core (10) comprises an assembly of several single-piece angular sectors arranged in azimuth around a central axis (X2-X2) of the tool (1), according to an alternation of sectors called "keys" (20), and sectors called "vaults" (21), supported and locked in position by the keys (20), the vaults (21) forming sectors complementary to the keys (20) and in which each key or key segment (20) and each vault or vault segment (21) comprises its own circuit (33, 34) for supplying the pressurized fluid, during the step (S5) of supporting the pressure increase, the pressurized fluid is injected into the circuit (33, 34) for supplying each key (20) and each vault (21).

19. Method according to any one of claims 16 to 18, in which the fluid is injected at a progressive pressure increasing until reaching a pressure of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, in a linear manner to reach a first pressure (PI) of between 20 bars and 35 bars for a first duration (Tl) of between 50s and 100s, for example equal to 60s, then following a second slope for a second duration (T2) of between 120s and 200s, for example equal to 150s, to reach a molding pressure (P2) of between 35 bars and 80 bars, preferably between 50 bars and 70 bars, preferably between 50 bars and 55 bars.

20. Method according to any one of claims 16 to 19, in which the injection of the pressurized fluid carried out in step (S5) of supporting the pressure increase starts after a duration of between 0s and 10s after the start of the cooking step (S4).

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