Process and apparatus for making multilayer annular components in building of tyres for vehicles

Abstract

During the making of tyres for vehicles, one or more multilayer annular components (7) are formed, each comprising annular layers (7a, 7b) radially superimposed on each other. One or more of the annular layers (7a, 7b) are made through respective forming cycles, each comprising: a) winding a semifinished product (S) according to a substantially cylindrical conformation around a building drum (13) comprising two half-drums (15) mutually aligned along a rotation axis (X); b) mutually moving away said half-drums along the rotation axis (X) by partially extracting them from the semifinished product, in order to generate or enlarge an annular opening (16) between the mutually moved-apart half-drums; c) radially expanding, through the annular opening (16), a profiler drum (17) coaxial with the building drum (13) in order to shape the semifinished product (S) according to an arched axial profile in conformity with an expansion surface (19) presented in radially outer position by the profiler drum.

Description

[0001] PROCESS AND APPARATUS FOR MAKING MULTILAYER ANNULAR COMPONENTS IN BUILDING OF TYRES FOR VEHICLES

[0002] The present invention relates to a process for making multilayer annular components in building of tyres for vehicles. The present invention further relates to a station or apparatus for making multilayer annular components in building of tyres for vehicles. In the example described herein, the invention is used for making a belt structure for motorcycle tyres. However, the invention may also be conveniently used for making annular tyre components different from the belt structure and usable not only on tyres for motorcycles, but also for motor vehicles, trucks, etc. A tyre for vehicle wheels generally comprises a carcass structure comprising at least one carcass ply having respectively opposite terminal flaps engaged with respective annular anchoring structures, integrated in the areas usually identified by the name of "beads", having an inner diameter substantially corresponding to a so-called "fitting diameter" of the tyre on a respective mounting rim.

[0003] The carcass structure is associated with a belt structure which may comprise one or more belt layers, arranged in radial superposition with respect to each other and with respect to the carcass ply, having textile, metallic or hybrid reinforcement cords with crossed orientation and / or substantially parallel to the circumferential development direction of the tyre (at 0 degrees). A tread band is applied in a position radially outer to the belt structure, also made of elastomeric material like other semifinished products making up the tyre.

[0004] RECTIFIED SHEET (RULE 91) ISA / EP Respective sidewalls of elastomeric material may further be applied in an axially outer position on the lateral surfaces of the carcass structure, each extending from one of the lateral edges of the tread band up at the respective annular anchoring structure to the beads. In "tubeless" tyres, an airtight coating layer, usually called "liner", covers the inner surfaces of the tyre. The carcass structure and the belt structure may be made separately of each other in respective work stations, to be mutually assembled at a later time.

[0005] More specifically, the manufacture of the carcass structure provides first that the carcass ply or plies are applied on a building drum, to form a so-called "carcass sleeve" substantially cylindrical. The annular anchoring structures to the beads are fitted or formed on the opposite terminal flaps of the carcass ply or plies, which are then looped back around the annular structures themselves so as to enclose them in a sort of loop.

[0006] A so-called "crown structure" is manufactured on a second drum or auxiliary drum in the shape of an outer sleeve comprising one or more belt layers applied in mutual radial superimposition, and optionally the tread band in a radially outer position to the belt layer(s). The crown structure is then picked up from the auxiliary drum to be coupled to the carcass sleeve. To this end, the crown structure is arranged coaxially around the carcass sleeve, after which the carcass ply or plies is / are shaped according to a toroidal configuration by mutual axial approach of the beads and concurrent introduction of fluid under pressure into the carcass sleeve, so as to cause a radial expansion of the carcass plies up to make them adhere against the inner surface of the crown structure.

[0007] 2

[0008] RECTIFIED SHEET (RULE 91) ISA / EP The assembly of the carcass sleeve with the crown structure can be carried out on the same drum used for making the carcass sleeve, in which case it is called "single step building process" or "unistage process".

[0009] Building processes of the so-called "two-step" type are also known, in which a so-called "first-step drum" is used for making the carcass sleeve, while the assembly between the carcass sleeve and the crown structure is carried out on a so-called "second-step drum" or "shaping drum", on which the carcass sleeve picked up from the first-step drum and then the crown structure picked up from the auxiliary drum are transferred.

[0010] The terms "radial" and "axial" and the expressions "radially inner / outer" and "axially inner / outer" are used referring to the radial direction and the axial direction of the tyre, i.e. to a direction perpendicular to the axis of rotation of the tyre and a direction parallel to the axis of rotation thereof, respectively. A radial plane of the tyre contains the rotation axis thereof.

[0011] The terms "circumferential" and "circumferentially" are instead used to refer to the annular development of the tyre, identifying with this expression the development assumed by the tyre along the rolling direction in operating conditions.

[0012] "Rotation axis" of a green tyre means the axis corresponding to the rotation axis of the vulcanised tyre when mounted in operating conditions on a respective mounting rim.

[0013] The term "width" means an axial dimension of the tyre or a component thereof. The term "length" refers to a circumferential dimension of a tyre component.

[0014] RECTIFIED SHEET (RULE 91) ISA / EP The term "component" of the tyre means any portion of the tyre capable of performing its own function or part of it.

[0015] The term "multilayer annular component" of the tyre means a component of the tyre comprising a plurality of layers radially superimposed with respect to a rotation axis of the tyre, wherein said plurality of layers comprises at least one radially outer annular layer and one radially inner annular layer and wherein each layer comprises at least one elastomeric material matrix. Preferably, a multilayer annular component of the tyre may be a set comprising two or more belt layers and in particular it may be a belt structure or, more generally, a multilayer annular component may be a set comprising two or more layers intended to be part of the green tyre, each selectable for example from: liner, underliner, anti-abrasive inserts, bead core, fillers in the bead area, carcass ply(ies), belt layer(s), belt underlayer, tread band underlayer, sidewalls, sidewall inserts, tread band, etc.

[0016] The term "multilayer component being processed" means the multilayer component during the building thereof, optionally comprising an increasing number of layers starting from a radially outer annular layer and excluding the radially inner annular layer which completes the multilayer component.

[0017] The term "elastomeric material" is used to designate a composition comprising at least one elastomeric polymer and at least one reinforcement filler. Preferably, such composition further comprises additives such as, for example, a cross-linking agent and / or a plasticiser. Due to the presence of the crosslinking agent, such material may be cross-linked by heating, so as to form the final manufactured article. The term "semifinished product" means a prefabricated product, i.e. a product manufactured before the production of the tyre and generally outside the building plant. The product is preferably prefabricated at full width, i.e. with its own pre-sized width so as to be equal to the width (measured in an axial direction of the tyre) of the layer of the component that the semifinished product is adapted to form. The semifinished product may be made of elastomeric material only, i.e. comprise only an elastomeric matrix, or it may be reinforced with at least one reinforcement cord made of textile and / or metallic and / or hybrid material.

[0018] Tyre for two-wheeled vehicles, in particular motorcycles, means a tyre whose curvature ratio is approximately between about 0.15 and about 0.45.

[0019] Curvature ratio in relation to a tyre (or a portion thereof or a drum) means the ratio of the distance of the radially outer point of the tread band (or of the outer surface or of the drum) from the line passing by the laterally opposite ends of the tread band itself (or of the outer surface itself or of the drum), measured on a radial plane of the tyre (or of said portion thereof or of the drum) or on a plane containing the rotation axis thereof (of the same or of the drum), to the distance measured along the chord of the tyre (or of a portion thereof or of the drum) between said ends.

[0020] The Applicant has observed that the building of a green tyre generally involves the making of at least one multilayer annular component by superimposed deposition of two or more annular layers starting from the radially inner annular layer towards the radially outer annular layer. For example, in document WO 2021 / 124241, on behalf of the same Applicant, a process for making belt structures is described according to which a first and a second belt layer are deposited on a cylindrical drum. The belt layers are subsequently removed from the cylindrical drum and placed on a further toroidal drum. A so-called zero degree belt layer is then made around the belt layers, obtained by winding one or more cords according to axially placed circumferential turns, so as to obtain the desired toroidal shape of the set of belt layers.

[0021] Document US 4,288,265 describes a process for building tyres, wherein the making of a belt structure involves a first and a second semifinished product in the form of a strip being wound in succession around an auxiliary drum of the type having a plurality of axial teeth circumferentially distributed to define a substantially cylindrical surface. The drum houses an expandable part composed of a plurality of sectors each having a convex radially outer surface. The sectors are radially movable between the teeth of the drum between a rest position, in which they are radially arranged with their entire convex surface within the cylindrical surface defined by the drum itself, and a working position, in which they protrude radially between the teeth of the drum so as to impose a toroidal shape according to a convex axial profile on the annular layers previously formed thereon.

[0022] The Applicant has observed that the handling necessarily carried out on the semifinished products for the purpose of the transfer thereof from one drum to another tends to increase processing dead times, to the detriment of productivity. Furthermore and, above all, such handling tends to introduce processing inaccuracies which may negatively affect the quality of the final product, resulting for example from the difficulty in obtaining a perfectly centred positioning of the products during the operations of disengagement from one drum and engagement on another drum.

[0023] The Applicant has also observed that the use of a drum of the type described in US 4,288,265 with sectors operating between the teeth of the drum itself determines a significant surface discontinuity of the drum, which is particularly undesirable during the shaping, when the sectors of the drum must transmit significant stresses on the annular semifinished products to determine the shaping thereof according to the desired profile. The radially expandable sectors are in fact in the form of plates arranged radially with respect to the geometric axis, interspersed with each other by through axial discontinuities (voids). It follows that the annular layers subjected to the action of the drum undergo an uneven application of the stresses that must impose the shaping thereof during the expansion of the drum itself, with the consequent risk of causing anomalous distortions and structural discontinuities in the final product.

[0024] The Applicant has also observed that in the prior art, the radial expansion of the semifinished products already coupled for the purposes of the toroidal shaping thereof may cause the presence of high stresses which are generated at the interface between two radially adjacent layers, due to the mutual adhesion between such layers and to the different expansion between the axially peripheral portions and the axially central portion of the multilayer component. These stresses may generate differentiated narrowing and widening in the material, giving rise to imperfections such as folds and / or misalignment of the edges,

[0025] 7

[0026] RECTIFIED SHEET (RULE 91) ISA / EP especially when one or more layers incorporate reinforcement cords arranged parallel to each other and crossed with respect to those of at least one radially adjacent annular layer which, during radial expansion, tend to rotate in respectively opposite directions while remaining incorporated within the elastomeric matrix.

[0027] The Applicant has also verified that the above emerges particularly clearly, but not exclusively, in the production of tyres with a high curvature ratio, as for example typically verified in tyres for two-wheeled vehicles. In other words, the Applicant has verified that the problems listed above, which affect the effective and constant reproducibility of the footprint area prefigured in the design step, are more relevant precisely in those tyres in which high reliability of the behaviour is required in order to achieve high driving safety.

[0028] The Applicant has perceived that the possibility of expanding the sectors of a forming drum through an annular and continuous access opening present in a deposition drum bearing the annular layers formed thereon would make it possible to use a forming drum having a greater surface continuity than that imposed by the prior art.

[0029] The Applicant has therefore found that by using a deposition drum composed of two axially separable half-parts to create or expand an annular opening, and by housing inside it a shaping drum expandable through such annular opening, it is possible to obtain greater precision and repeatability in the mutual positioning of semifinished products and a qualitative improvement of the product.

[0030] More in particular, the invention relates to a process for making

[0031] 8

[0032] RECTIFIED SHEET (RULE 91) ISA / EP multilayer annular components in building of tyres for vehicles.

[0033] Preferably, each multilayer annular component comprises annular layers that are radially superimposed on each other.

[0034] Preferably, one or more of said annular layers are made through respective forming cycles.

[0035] Preferably, each forming cycle comprises: a) winding a semifinished product according to a substantially cylindrical shape around a building drum comprising two halfdrums mutually aligned along a rotation axis.

[0036] Preferably, each forming cycle comprises: b) mutually moving away said half-drums along the rotation axis by partially extracting them from the semifinished product, in order to generate or enlarge an annular opening between the mutually moved-apart half-drums.

[0037] Preferably, each forming cycle comprises: c) radially expanding, through the annular opening, a profiler drum coaxial with the building drum, in order to shape the semifinished product according to an arched axial profile in conformity with an expansion surface presented in radially outer position by the profiler drum.

[0038] In a further aspect, the invention relates to an apparatus for making multilayer annular components in the building of tyres for vehicles.

[0039] Preferably, a substantially cylindrical building drum is provided, comprising two half-drums mutually aligned and movable along a rotation axis.

[0040] Preferably, the building drum is switchable between a deposition condition in which respective terminal edges axially facing each other of the half-drums are mutually approached, and a shaping condition in which said terminal edges are mutually spaced.

[0041] Preferably, at least one feeder is provided, configured for applying semifinished products around a deposition surface presented externally by the building drum in the deposition condition.

[0042] Preferably, a profiler drum is provided, coaxially arranged within the building drum.

[0043] Preferably, the profiler drum has an expansion surface that is radially external and axially convex.

[0044] Preferably, the profiler drum is switchable between a first operating condition, in which the expansion surface has a maximum diameter smaller or equal to a diameter of the deposition surface, and a second operating condition in which the expansion surface radially projects through an annular opening defined between said half-drums.

[0045] The Applicant believes that the execution of the forming cycles on the individual layers in succession starting from the radially outermost layer significantly simplifies the shaping operations which, being executed on the individual semifinished products, are much less complex and free from problems that emerge in the prior art, where the shaping is necessarily executed on already coupled semifinished products.

[0046] In at least one of the aforementioned aspects, a convenient embodiment of the invention comprises one or more of the preferential features listed below.

[0047] Preferably, at least one of the forming cycles further comprises: d) positioning a retention ring coaxial in radial superimposition around the semifinished product previously wound on the building drum.

[0048] Preferably, at least one of the forming cycles further comprises: e) engaging, against the retention ring, a radially outer annular layer formed by the shaped semifinished product.

[0049] Preferably, at least one of the forming cycles further comprises: f) retaining the radially outer annular layer against the retention ring, while the profiler drum is radially contracted.

[0050] Preferably, action d) is performed before completing action c). Preferably, action e) is performed at the end of action c) or after it.

[0051] Preferably, the action c) comprises switching the profiler drum between a first operating condition, in which the radially outer expansion surface of the profiler drum has a maximum diameter smaller than or equal to a diameter of a deposition surface presented externally by the building drum, and a second operating condition in which the expansion surface radially projects through the annular opening.

[0052] Preferably, at least one of said semifinished products is made in the form of a strip wound circumferentially around the building drum.

[0053] Preferably, at least one of said semifinished products has a length substantially equal to a circumferential extension of the building drum.

[0054] Preferably, at least one of said semifinished products comprises reinforcement cords parallel to each other, incorporated in a matrix of raw elastomeric material. Preferably, terminal portions of the semifinished product are joined together at the end of the winding of the semifinished product.

[0055] Preferably, terminal portions of the semifinished product are joined together before moving said half-drums apart from each other.

[0056] Preferably, terminal portions of the semifinished product are mutually superimposed and joined together by pressing with a radial thrust action towards the building drum.

[0057] The half-drums of the building drum in mutual approach lend themselves to providing an effective support to facilitate the execution of the joint.

[0058] Preferably, before completing the action c), the semifinished product has axially opposite terminal flaps arranged each around one of said half-drums.

[0059] The semifinished product therefore remains effectively retained by the building drum so as to simplify the correct engagement thereof by the profiler drum according to precise positioning.

[0060] Preferably, the mutual moving away of the half-drums continues progressively during action c).

[0061] Preferably, the mutually moving away of the half-drums progressively continues during the action c), up to disengaging the semifinished product simultaneous with a complete transfer of the semifinished product on the profiler drum.

[0062] The disengagement of the semifinished product from the building drum therefore occurs after the profiler drum has come into contact with an axially inner part of the semifinished product itself, so as not to compromise the correct positioning thereof. Preferably, said annular layers comprise at least one radially inner annular layer and one radially outer annular layer.

[0063] Preferably, provision is made for: making at least one radially outer annular layer; making at least one radially inner annular layer; coupling said at least one radially inner annular layer against a radially inner surface of a multilayer annular component being processed comprising said at least one radially outer annular layer.

[0064] Preferably, the forming cycles comprise an initial forming cycle for making the radially outer annular layer and a final forming cycle for making the radially inner annular layer.

[0065] Preferably, coupling said at least one radially outer annular layer comprises, during the execution of the initial forming cycle: d) positioning a retention ring coaxial in radial superimposition with respect to the semifinished product wound on the building drum.

[0066] Preferably, coupling said at least one radially outer annular layer comprises, during the execution of the initial forming cycle: d) positioning a retention ring coaxial in radial superimposition and axially centred with respect to the semifinished product wound on the building drum.

[0067] Preferably, coupling said at least one radially outer annular layer comprises, during the execution of the initial forming cycle: e) engaging, against the retention ring, the radially outer annular layer formed by the shaped semifinished product.

[0068] Preferably, coupling said at least one radially outer annular layer comprises, during the execution of the initial forming cycle: f) retaining the radially outer annular layer against the retention ring, while the profiler drum is radially contracted. Preferably, coupling said at least one radially inner annular layer comprises, during the execution of the final forming cycle: d) coaxially positioning the retention ring in radial superimposition with respect to the semifinished product previously wound around the building drum.

[0069] Preferably, coupling said at least one radially inner annular layer comprises, during the execution of the final forming cycle: d) positioning a retention ring coaxial in radial superimposition and axially centred with respect to the semifinished product wound on the building drum.

[0070] Preferably, coupling said at least one radially inner annular layer comprises, during the execution of the final forming cycle: e) engaging, against the multilayer annular component being processed borne by the retention ring, the radially inner annular layer formed by the shaped semifinished product. Preferably, the forming cycles also comprise at least one intermediate forming cycle in order to make at least one intermediate annular layer radially interposed between the radially outer annular layer and the radially inner annular layer. Preferably, it is also contemplated to couple each intermediate layer against the radially inner surface of the multilayer annular component being processed during the execution of the intermediate forming cycle, through: d) coaxially positioning the retention ring in radial superimposition with respect to the semifinished product wound around the building drum. Preferably, it is also contemplated to couple each intermediate layer against the radially inner surface of the multilayer annular component being processed during the execution of the intermediate forming cycle, through: d) positioning the retention ring coaxial in radial superimposition and axially centred with respect to the semifinished product wound around the building drum. Preferably, it is also contemplated to couple each intermediate layer against the radially inner surface of the multilayer annular component being processed during the execution of the intermediate forming cycle, through: e) engaging, against the multilayer annular component being processed borne by the retention ring, the intermediate layer formed by the shaped semifinished product.

[0071] Preferably, at the end of at least one of said forming cycles: radially contracting the profiler drum.

[0072] Preferably, at the end of at least one of said forming cycles: axially approaching the half-drums of the building drum.

[0073] The profiler drum and the building drum are thus arranged for the making of a new multilayer component.

[0074] Preferably, at the end of at least one of said forming cycles: axially translating the retention ring, in order to place it in a waiting position axially displaced with respect to the profiler drum.

[0075] Space is thus freed up around the building drum and the profiler drum, to facilitate the deposition of a new semifinished product for the purpose of executing a new forming cycle.

[0076] Preferably, after the coupling of said at least one radially inner annular layer: radially expanding the retention ring in order to disengage it from the multilayer annular component borne by the profiler drum.

[0077] Preferably, after the coupling of said at least one radially inner annular layer: axially translating the retention ring with respect to the profiler drum.

[0078] Preferably, after the coupling of said at least one radially inner annular layer: transferring to a subsequent work station the multilayer annular component together with the profiler drum.

[0079] The multilayer component borne by the same profiler drum used for the making thereof is therefore suitable for being transferred for the purpose of executing further processing, without undergoing additional handling.

[0080] Preferably, transferring to the next work station comprises: engaging the multilayer annular component to a grip member.

[0081] Preferably, transferring to the next work station comprises: radially contracting the profiler drum in order to disengage it from the multilayer annular component.

[0082] Preferably, it is also contemplated, after the transfer to the next work station: repositioning the profiler drum coaxial between the halfdrums of the building drum.

[0083] Preferably, it is also contemplated, after the transfer to the next work station: mutually approaching the half-drums of the building drum. The profiler drum and the building drum are thus arranged for the making of a new multilayer component.

[0084] Preferably, it is also contemplated, after the transfer to the next work station: positioning a further profiler drum coaxial between the half-drums of the building drum.

[0085] Preferably, it is also contemplated, after the transfer to the next work station: mutually approaching the half-drums of the building drum. Preferably, after the coupling of said at least one radially inner annular layer: disengaging the profiler drum from the multilayer annular component borne by the retention ring.

[0086] Preferably, after the coupling of said at least one radially inner annular layer: translating the retention ring in order to transfer, to a subsequent work station, the multilayer annular component. Preferably, in the second operating condition, the maximum diameter of the expansion surface is greater than the diameter of the deposition surface.

[0087] Preferably, a retention ring is further provided, positionable coaxial outside the building drum, in radial superimposition, preferably axially centred, with respect to the profiler drum, and configured for engaging a multilayer annular component being processed comprising at least one radially outer annular layer.

[0088] Preferably, the building drum is also switchable into an open condition in which the half-drums are mutually moved away from each other to a greater extent with respect to the shaping condition, in order to allow disengagement of the profiler drum from the building drum through the annular opening.

[0089] Preferably, the expansion surface of the profiler drum has a curvilinear axial profile defining a convexity directed towards a radially outer direction.

[0090] Preferably, the expansion surface of the profiler drum has a curvature ratio of between about 0.15 and about 0.45.

[0091] Preferably, the expansion surface of the profiler drum has a plane of axial symmetry axially centred between axially inner edges of the half-drums.

[0092] Preferably, the expansion surface of the profiler drum lacks through axial interruptions.

[0093] Preferably, each half-drum of the building drum comprises a plurality of circumferentially distributed building sectors.

[0094] Preferably, the building sectors of each half-drum are radially movable in order to modulate an external diameter of the deposition surface.

[0095] Preferably, each half-drum comprises a discoid flange carrying radial guide seats each slidably engaging one of the building sectors.

[0096] The radial mobility of the building sectors allows easy adaptation of the diameter of the deposition surface for the processing of multilayer components of different sizes.

[0097] Further features and advantages will become more apparent from the detailed description of a preferred but non-exclusive embodiment of a process and apparatus for making multilayer annular components in the building of tyres for vehicles, according to the present invention. Such description is given hereinafter with reference to the accompanying drawings, provided only for illustrative and, therefore, non-limiting purposes, in which:

[0098] - Figures 1-13 schematically illustrate some elements of an apparatus for making multilayer annular components in the building of tyres for vehicles, at different moments of a building process;

[0099] - Figure 14 schematically illustrates a layout of a plant for building a green tyre equipped with the apparatus according to the present invention;

[0100] - Figure 15 schematically shows a radial half-section of a tyre which may be manufactured according to the present invention.

[0101] With reference to Figure 14, reference numeral 1 generally indicates a plant for building green tyres.

[0102] Plant 1 is designed to manufacture tyres 2 (Figure 15) comprising at least one carcass ply 3 preferably internally coated with a layer of impermeable elastomeric material or so-called liner 4. Two annular anchoring structures 5 comprising each a so-called bead core 5a preferably bearing an elastomeric filler 5b in radially outer position are engaged to respective terminal flaps 3a of the carcass ply or plies 3. The annular anchoring structures 5 are integrated in the proximity of zones usually identified by the name of "beads", at which the engagement between the tyre 2 with a respective mounting rim (not shown) usually occurs.

[0103] A crown structure 6 comprises at least one belt structure 7 and a tread band 8 circumferentially superimposed on the belt structure 7. The crown structure 6 is circumferentially arranged around the carcass ply(ies) 3. The belt structure 7 comprises at least two layers: a radially outer belt layer 7a and a radially inner belt layer 7b. Optionally, one or more further radially intermediate belt layers may be provided between the radially outer belt layer 7a and the radially inner belt layer 7b.

[0104] The belt layers may comprise parallel textile and / or metallic and / or hybrid cords, preferably arranged in an inclined orientation with respect to the circumferential development direction of the green tyre 2 and respectively crossed between belt layers adjacent to each other.

[0105] The tyre 2 further comprises two sidewalls 9, extending each from the respective bead to a corresponding lateral edge of the tread band 8, applied in laterally opposite positions on the carcass ply(ies) 3.

[0106] The tyre 2 may also comprise further elements depending on the intended use.

[0107] Preferably, it is a tyre for motorcycles or other two-wheeled vehicles having a curvature ratio approximately between about 0.15 and about 0.45.

[0108] The plant 1 (Figure 14) is equipped with an apparatus for making multilayer annular components in the building of tyres for vehicles, according to the present invention. In the example described and illustrated herein, such apparatus is represented by a station for building belt structures indicated as a whole with reference numeral 11, cooperating with a station for building carcass structures 10 and an assembling station 37. The belt structure 7 therefore represents, in the illustrated example, a multilayer annular component which may be made using the apparatus represented by the station for building belt structures 11. The radially outer belt layer 7a and the radially inner belt layer 7b respectively represent a radially outer annular layer and a radially inner annular layer forming part of the multilayer annular component. The belt structure 7 may optionally have one or more intermediate belt layers (not shown), radially interposed between the radially outer belt layer 7a and the radially inner belt layer 7b, and representing respective intermediate annular layers radially interposed between the radially outer annular layer and the radially inner annular layer forming part of the multilayer annular component.

[0109] In the remainder of the present description, any reference to the station for building belt structures 11 and to the belt structure 7 will be understood as also applied to the apparatus for making multilayer annular components and to each multilayer annular component obtainable therewith. Similarly, any reference to the radially outer belt layer 7a, to the radially inner belt layer 7b and / or to any possible intermediate belt layer will also be understood as applied respectively to the radially outer annular layer, to the radially inner annular layer and / or to any intermediate annular layer forming part of the multilayer annular component.

[0110] The station for building carcass structures 10 is adapted to produce, for example according to known methods, a carcass sleeve 12 (Figure 14) having a substantially cylindrical shape. The carcass sleeve 12 includes said at least one carcass ply 3, preferably internally lined by liner 4, and having the respective terminal flaps 3a engaged, for example through looping back, to the respective annular anchoring structures 5. If necessary, the carcass sleeve 12 may also include sidewalls 9 or first portions of the same, extending each starting from a respective bead 6.

[0111] The station for building belt structures 11 is adapted to produce the belt structure 7 comprising at least the radially outer belt layer 7a and the radially inner belt layer 7b, as well as, where required, one or more of the intermediate belt layers not present in the embodiment described and illustrated.

[0112] With reference to Figures 1-13, the station for building belt structures 11 comprises a building drum 13 rotating around a rotation axis "X" which, with reference to the tyre 2, corresponds to a rotation axis of the tyre itself.

[0113] The building drum 13 has a radially outer cylindrical surface, not necessarily continuous, defining a building surface 14 arranged around the rotation axis "X".

[0114] The building drum 13 comprises two half-drums 15 which are movable relative to each other in an axial direction along the rotation axis X to move towards and away from each other. Preferably, each half-drum 15 comprises a slide preferably in the form of a flange 15a having a disc-like shape, on which building sectors 15b are mounted circumferentially distributed around the "X" axis. The building sectors 15b, preferably mounted cantilevered with respect to the respective flanges 15a, have respective axially inner ends facing an axial middle line zone "M" of the building drum 13. For simplicity of illustration, Figures 1- 13 show a single building sector 15b for each half-drum 15. In each of the half-drums 15, the axially inner ends of the building sectors 15b are preferably aligned along a common circumference. The axially inner ends of the building sectors 15b define terminal edges axially facing each other of the respective half-drums 15. In each of the half-drums 15, the building sectors 15b, or at least axially inner portions thereof bearing said axially inner ends, are movable axially with respect to the respective flange 15a moving away from and towards the axial middle line zone "M" of the building drum 13. The building drum 14 is therefore switchable between a deposition condition in which respective terminal edges axially facing each other of the halfdrums 15 are mutually approached, and a shaping condition in which said terminal edges are mutually spaced; At least in the deposition condition, i.e. in the approached position of the two half-drums 15 and the building sectors 15b, the building sectors 15b define the building surface 14.

[0115] The axial distancing of the building sectors 15b from the axial middle line zone "M" of the building drum 13, towards the open condition, creates and / or enlarges an annular opening 16 (Figures 4-7 and 11-13) arranged centrally with respect to the building surface 14.

[0116] Preferably, the slides or flanges 15a are movable away from each other, to switch the building drum 13 into an open condition in which the half-drums 15 are moved away from each other to a greater extent than in the shaping condition. The mutual and preferably symmetrical distancing of the two halfdrums 15, in particular of the two flanges 15a, allows access to the area within the building drum 13.

[0117] The building drum 13 is preferably radially expandable and contractable, to modulate an outer diameter of the deposition surface. The building sectors 15b may in fact be slidably engaged and fixedly positioned along respective radial guide seats 15c (Figure 1) arranged in each of the flanges 15a. The radial expansion / contraction of the building sectors 15b must preferably be synchronous and self-centring. The building sectors 15b may be positioned at a different diameter during the making of the radially outer 7a, radially inner 7b or intermediate belt layers but on both sides they must be positioned on the same diameter.

[0118] The station for building belt structures 11 further comprises a profiler drum 17. When the two half-drums 15 are moved away from each other with the building drum 13 in the open condition, the profiler drum 17 may be inserted through the annular opening 16 within the building drum 13 and mounted coaxial thereto, as shown for example in Figures 1-13 and, again through the annular opening 16, it may be extracted from the building drum 13 and moved away therefrom, as shown in Figure 14. Preferably, when mounted within the building drum 13, the profiler drum 17 is supported with respect to the half-drums 15 for example by means of a mandrel / tailstock coupling made at the flanges 15a.

[0119] The profiler drum 17 comprises a profiled body 18 having a radially outer surface, not necessarily continuous, defining a radially outer expansion surface 19 arranged around the rotation axis "X". The expansion surface 19 is axially convex, i.e. it has a rounded axial profile corresponding to the axial profile of the belt structure 7 so that the belt structure 7 has a toroidal shape. More specifically, the expansion surface 19 has a curvilinear axial profile defining a convexity facing a radially outer direction, with an axial symmetry plane thereof axially centred between the axially inner edges of the half-drums 15, at the axial middle line zone "M". Belonging to two different drums, the expansion surface 19 and the building surface 14 are structurally distinct from each other.

[0120] Preferably, the profiled body 18 comprises profiling sectors 18a circumferentially distributed around a central shaft 20 of the profiler drum 17 and defining the expansion surface 19. For simplicity of illustration, Figures 1-13 show only one profiling sector 18a.

[0121] The profiler drum 17 is radially expandable and contractable between a first operating condition, in which the expansion surface 19 is in a radially contracted condition (for example shown in Figures 1 and 2), so as to have its own maximum diameter less than or equal to a diameter of the deposition surface 14, and a second operating condition, in which the expansion surface 19 is in a radially expanded condition (for example shown in Figures 3-7) to a maximum diameter greater than the diameter of the deposition surface 14, so as to protrude radially through the annular opening 16.

[0122] According to a possible embodiment, the sectors 18 of the profiled body 18 are movable, preferably simultaneously, from said first operating condition in which they are close to the central shaft 20, to the second operating condition in which said sectors are moved away from the central shaft. To this end, it may be contemplated that the sectors 18a are borne by respective guiding members 21, preferably telescopically extendable, extending radially from the central shaft 20.

[0123] The profiler drum 17 comprises movement members 22 configured to implement the transition between the two aforementioned operating conditions. According to a possible embodiment, the movement members 22 comprise a screw-nut system 23 operationally interposed between the sectors 18a of the profiled body 18 and the central shaft 20. For example, the screw-nut system 23 comprises a plurality of pairs of control levers 24 associated with respective pairs of control nuts 25 operatively engaged on axially opposed threads 26a, 26b, respectively right-handed and left-handed, of a threaded bar 27 associated with the central shaft 20. According to this example, the rotation of the threaded bar 27 determines an opposing axial movement of the control nuts 25, which corresponds to a radial movement of the sectors 18a of the profiled body 18, towards the first or second operating condition depending on the direction of rotation of the threaded bar 7.

[0124] Preferably, the profiler drum 17, and in particular the expansion surface 19, at least in the second operating condition has a curvature ratio between about 0.15 and about 0.45, typically suitable for the production of tyres for motorcycles or other twowheeled vehicles. However, if necessary, curvature ratios of different values may be used, for example lower than those indicated above, for example suitable for the production of car or truck tyres.

[0125] The expansion surface 19 conveniently lacks through axial interruptions, so as to make the distribution of stresses more uniform during the expansion action. To this end, each sector 18a may have two circumferentially opposite coupling portions, each having a plurality of elongated protrusions extending in a circumferential direction, alternating with respective circumferentially elongated cavities. The protrusions of each sector slide into the respective cavities of the circumferentially adjacent sectors, and slide into the cavities themselves to accommodate the expansion and contraction movements of the forming drum. A technical solution of this type is used for example on a forming drum used to shape a carcass structure in patent US 10,611,110 B2, on behalf of the same Applicant, which is considered to be fully reported herein.

[0126] With reference to Figure 14, the plant 1 comprises a retention ring 28 associated with the station for building belt structures 11. The retention ring 28 comprises a support structure 29 arranged circumferentially around the rotation axis "X". The support structure 29 is preferably slidably mounted on one or more linear guides 30, to allow the translation of the support structure 29 parallel to the rotation axis "X".

[0127] With reference for example to Figure 1, a plurality of grip elements 31 circumferentially distributed around the rotation axis "X" are mounted on the support structure 29 (schematically represented).

[0128] For simplicity of illustration, Figures 1-13 show only one grip element 31.

[0129] Each of the grip elements 31 is preferably radially movable between a first position in which it is brought closer to the rotation axis "X" (for example illustrated in Figure 7) and a second position in which it is moved away from the rotation axis "X" (for example illustrated in Figure 1).

[0130] The movement of the grip elements 31 may be achieved mechanically (for example by means of a toothed ring nut, a cam system and / or arms) and / or hydraulically.

[0131] With reference to Figure 1, each grip element 31 comprises a body 32 having a retention surface 33 which faces towards the rotation axis "X" and which is associated with a retention system preferably by vacuum, for example a suction cup and / or aspirator system. The set of retention surfaces 33 of the grip elements 31 constitutes an overall retention surface of annular shape, not necessarily continuous.

[0132] With reference to Figure 1, a dispensing station 35 suitable for dispensing semifinished products "S" also operates within the station for building belt structures 11. Preferably, the dispensing station 35 comprises at least one feeder 36, for example in the form of a conveyor belt, configured for carrying a semifinished product "S" up to the building drum 13 to cause the application thereof around the deposition surface 14 while the building drum 13 rotates around the rotation axis "X".

[0133] The station for building belt structures 11 is suitable for making the belt structures 7 by means of a process for making multilayer annular components in the building of tyres 2, according to the present invention. Such process is described below with specific reference to the making of belt structures 7. However, it may also be conveniently used for making, in addition or alternatively, different multilayer annular components, such as for example carcass sleeves 12, tread bands 8 or other, each comprising a plurality of annular layers radially superimposed on each other, with respect to the rotation axis X and / or to the rotation axis of the resulting tyre 2.

[0134] In the making of the belt structure 7, it is conveniently provided that one or more of said radially outer belt layer 7a, radially inner belt layer 7b and any intermediate belt layers are made through respective consecutive forming cycles, each starting from the respective semifinished product "S". The semifinished product "S" is made in the form of a strip having a length substantially equal to the circumferential development of the building drum 13, and may comprise the aforementioned reinforcement cords incorporated in a matrix of raw elastomeric material.

[0135] More specifically, an initial forming cycle for making the radially outer belt layer 7a and a final forming cycle for making the radially inner belt layer 7b are preferably provided. If required, one or more intermediate forming cycles may also be provided for making one or more intermediate belt layers (not shown) radially interposed each between the radially outer belt layer 7a and the radially inner belt layer 7b.

[0136] In each forming cycle, it is contemplated that the semifinished product "S" coming from the feeder 36 is wound according to a substantially cylindrical shaping around the building drum 13, and in particular around the first cylindrical deposition surface 14. In this step, the building drum 13 has the two half-drums 15 and the respective building sectors 15b placed next to each other in the building condition, so that the annular opening 16 is substantially absent or has minimal axial dimension. The profiler drum 17 is arranged within the building drum 13 and in the first operating condition thereof, in which the expansion surface 19 is in a radially contracted condition.

[0137] With reference to Figure 1, referring to the initial forming cycle aimed at making the radially outer belt layer 7a, the retention ring 28 is arranged in a waiting position, axially displaced with respect to an axial middle line zone "M" of the building drum 13.

[0138] With reference to Figure 2, following the alignment of the semifinished product "S" on the building surface 14 and the rotation of the building drum 13 around the rotation axis "X", the semifinished product "S" is wrapped around the building drum 13 forming the radially outer belt layer 7a in the form of a cylindrical sleeve coaxial with the rotation axis "X". In particular, the semifinished product "S" is deposited centrally between the two half-drums 15 at the axial middle line zone "M" of the building drum 13. At the end of the winding of the semifinished product "S", terminal portions of the latter are brought to fit together along a circumferential direction of the building drum 13, mutually superimposed and joined together. Such junction may be assisted by pressing with a radial thrust action towards the building drum 13, for example by a pressing roller not shown, which translates transversally to the semifinished product "S" along the mutually superimposed terminal portions.

[0139] With reference to Figure 3, the profiler drum 17 may be slightly expanded radially (arrow Fl) until the profiled body 18 approaches the semifinished product "S" wound around the building surface 14.

[0140] A mutual distancing of the half-drums 15 along the rotation axis "X" is then commanded, for example by moving the flanges 15a. In particular, with reference to Figure 4, the half-drums 15 are partially removed from the semifinished product "S" (arrows F2), so as to create or enlarge the annular opening 16 present therebetween. At the same time, the profiler drum 17 may be further expanded radially (arrow Fl).

[0141] With reference to Figure 5, the profiler drum 17 is further expanded radially (arrow Fl) so as to engage the semifinished product "S" through the annular opening 16 by exerting a radial thrust action towards the outside (according to the same arrow Fl) operating against a radially inner surface of the semifinished product "S". In other words, the profiler drum 17 is expanded radially through the annular opening 16, so as to shape the semifinished product "S" according to an arched axial profile according to the expansion surface 19.

[0142] The mutual distancing of the half-drums 15a continues progressively during the expansion of the profiler drum 17 until the semifinished product "S" is disengaged in conjunction with a complete transfer of the latter onto the profiler drum itself. The gradual removal of the half-drums 15a is preferably synchronised with the progressive expansion of the profiler drum 17, so that before the completion of the latter, the axially opposite terminal edges of the semifinished product "S" each remain fitted around one of the half-drums, to the advantage of the stability of the semifinished product itself.

[0143] In Figure 6, the radial expansion of the semifinished product "S" is complete. The profiler drum 17 is in fact in the second operating condition, with the expansion surface 19 thereof in a radially expanded condition. The half-drums 15a have moved further away axially (arrow F2), enlarging the annular opening 16 and disengaging from the semifinished product "S" upon reaching the opening condition. The profiler body 18 has passed through the annular opening 16 and the semifinished product "S" rests completely on the expansion surface 19.

[0144] With an axial movement along the linear guides 30 starting from the waiting position, the retention ring 28 is positioned coaxially in radial superimposition around the semifinished product "S", preferably in an axially centred position with respect to the latter in the axial middle line zone "M". The axial movement of the retention ring 28 may also be carried out after the winding of the semifinished product "S" around the deposition surface 14, before the radial expansion of the profiler drum 17 begins or during the expansion thereof.

[0145] The execution of the operations described above during the initial forming cycle determines the creation of the radially outer belt layer 7a, starting from the semifinished product "S" initially deposited in a substantially cylindrical shape on the deposition surface 14.

[0146] With reference to Figure 7, the radially outer belt layer 7a consisting of the shaped semifinished product "S", is then engaged against the retention ring 28, to be retained thereby while the profiler drum 17 is radially contracted to be returned to the first operating condition. To this end, it may be contemplated that the grip elements 31 are moved towards the respective first position approaching the rotation axis "X" (arrow F4), so that each retention surface 33 comes into contact with the radially outer surface of the radially outer belt layer 7a. Alternatively, the grip elements 31 may already be in the respective first position when the retention ring 28 is axially positioned in a centred position with respect to the semifinished product "S", so that the radially outer belt layer 7a may reach the retention surfaces 33 at the end of the expansion of the profiler drum 17.

[0147] With reference to Figure 8, the retention system is activated by vacuum, so as to exert a radial traction action towards the outside (arrows F5) operating on the radially outer belt layer 7a which is thus retained by the retention ring 28. The profiler drum 17 is contracted radially (arrow F6), cancelling the radial thrust action exerted thereby on the radially outer belt layer 7a. The profiled body 18 is completely retracted into the area within the building drum 13. The two half-drums 15 move closer to each other in the axial direction (arrows F7), closing the annular opening 16 and arranging the building drum 13 in the building condition, for making a new annular component, for example the inner belt layer 7b with the execution of the final forming cycle.

[0148] To this end, with reference to Figure 9, the retention ring 28 bearing the radially outer belt layer 7a is axially translated from the axial middle line zone "M" (arrow F8) to be placed again in the waiting position axially displaced with respect to the building drum 13 and to the profiler drum 17. The retention ring 28 in the waiting position frees the space surrounding the building drum 13, facilitating access to the feeder 36 for the purpose of winding a new semifinished product "S" aimed at making the radially inner belt layer 7b or of one of the aforementioned intermediate belt layers.

[0149] As visible in Figures 9 to 11, the execution of the final forming cycle, aimed at making the radially inner annular layer 7b, may be executed in a substantially similar way to the initial work cycle previously executed for making the radially outer layer 7a. With reference to Figure 12, with the completion of the expansion of the profiler drum 17 in the second operating condition, after the retention ring 28 has been placed back in radial superimposition with respect to the semifinished product "S" previously wound around the building drum 13, the radially inner belt layer 7b defined by the shaped semifinished product "S" is coupled against the radially inner surface of the radially outer belt layer 7a, i.e. of the belt structure 7 being processed borne by the retention ring 28. The stickiness of the raw elastomeric material used in the making of the semifinished products "S" allows a stable mutual adhesion of the radially inner annular layer and the radially outer annular layer.

[0150] As described above, between the initial forming cycle and the final forming cycle, one or more intermediate forming cycles may also be provided, where required, for making one or more intermediate belt layers, applied in succession internally to the radially outer belt layer 7a previously formed. Each intermediate forming cycle may be executed in a completely similar way to what has been said with reference to the final forming cycle, and is therefore not described further. Each intermediate belt layer is suitable for being coupled, during the execution of the respective intermediate forming cycle, against the radially inner surface of the belt structure 7 being processed, including the radially outer belt layer 7a and any intermediate belt layers previously formed, borne by the retention ring 28.

[0151] With reference to Figure 13, at the end of the radial expansion of the radially inner belt layer 7b with consequent formation of the belt structure 7 or other multilayer annular component, the retention ring 28 may be radially expanded by moving the grip elements 31 towards the second position in which they are moved away from the rotation axis "X" (arrow Fll), while the vacuum retention system is deactivated, thus cancelling the radial traction action, so as to release the belt structure 7 on the profiler drum 17 .

[0152] The retention ring 28 may be axially translated with respect to the profiler drum 17 to be returned to the waiting position of Figure 1. The half-drums 15 are in turn moved away from each other axially (arrows F12) and are positioned in the open condition, at a relative distance such as to allow complete access to the area within the building drum 13.

[0153] In this circumstance, the profiler drum 17 is suitable for being picked from the station for building belt structures 11 to be transferred to the assembling station 37, or another subsequent station contemplated in the building process, together with the belt structure 7 engaged thereon, to continue building the tyre 2. The assembling station 37 may conveniently be associated with a grip member 39 designed to receive the belt structure 7 borne by the profiler drum 17, to allow the subsequent coupling thereof with the carcass sleeve 12. The grip member 39, which may be made in a similar way to the retention ring 28 and therefore only schematically illustrated, may have an annular shape and include radially movable sectors, optionally operating in a vacuum using suction cups and / or aspiration systems. Preferably, the grip member 39 is movable in and out of the assembling station 37, for example on axes 40 parallel and perpendicular to a central axis "Y" of the assembling station 37.

[0154] Reference numeral 41 indicates a transfer device operating between the station for building belt structures 11 and the grip member 39 which equips the assembling station 37. The transfer device 41 may be implemented using a robot 42 adapted to retain the profiler drum 17 for picking it from the station for building belt structures 11 and transferring it towards the shaping station 37, inserting it within the grip member 39.

[0155] The belt structure 7 is therefore suitable for being transferred from the profiler drum 17 to the grip member 39, optionally with a radial contraction movement of the sectors of the latter and a subsequent radial contraction of the profiler drum 17, to then be brought into the shaping station 37 together with the grip member 39 moved along the axes 40.

[0156] In the meantime, the carcass sleeve 12 made - for example according to known methods - in the station for building carcass structures 10 is transferred to the shaping station 37 by means of loading devices 38, and positioned coaxially to the central axis «Y"

[0157] With a movement of the grip member 39 along the central axis "Y", the belt structure 7 is placed in an axially centred position around the carcass sleeve 12.

[0158] The assembling station 37, not described in detail as it may be implemented in a known manner, for example as described in the aforementioned U.S. patent 10,611,110 B2, is therefore suitable for shaping the carcass sleeve 12 causing a radial expansion according to a toroidal shape, for coupling it to the belt structure 7 retained by the grip member 39 and then completing the building of the tyre 2.

[0159] The profiler drum 17 is in turn suitable for being returned to the station for building belt structures 11, to begin the making of a new belt structure 7 or other multilayer annular component with a mutual approach of the half-drums 15 in the position of Figure 1.

[0160] Alternatively, the profiler drum 17 moved away from the shaping station 37 may be placed in a waiting warehouse (not shown), and the station for building belt structures 11 may be equipped with a further profiler drum 17, having geometric features different from the one used previously, for making a belt structure 7 of a tyre having different geometric and / or dimensional specifications. In a further embodiment not illustrated, it may be contemplated that the retention ring 28 is movable from the station for building belt structures 11 to the assembling station 37. In this case, at the end of the radial expansion of the radially inner belt layer 7b, the profiler drum 17 may be contracted towards the first operating condition, to release the belt structure 7 retained by the retention ring 28 which maintains the first radially contracted position. The retention ring is therefore suitable for transferring the belt structure 7 into the assembling station 37 and retaining it until it is fully coupled with the carcass sleeve 12 shaped according to a toroidal configuration, while the profiler drum 17 remains in the station for building belt structures 11 to start, for example, the making of a new belt structure.

Claims

CLAIMS1. Process for making multilayer annular components in building of tyres for vehicles, wherein each multilayer annular component (7) comprises annular layers (7a, 7b) that are radially superimposed on each other, wherein one or more of said annular layers (7a, 7b) are made through respective forming cycles each comprising: a) winding a semifinished product (S) according to a substantially cylindrical shape around a building drum (13) comprising two half-drums (15) mutually aligned along a rotation axis (X); b) mutually moving away said half-drums (15) along the rotation axis (X) by partially extracting them from the semifinished product (S), in order to generate or enlarge an annular opening (16) between the mutually moved-apart halfdrums (15); c) radially expanding, through the annular opening (16), a profiler drum (17) coaxial with the building drum (13), in order to shape the semifinished product (S) according to an arched axial profile in conformity with an expansion surface (19) presented in radially outer position by the profiler drum (17).

2. Process according to claim 1, wherein at least one of the forming cycles also comprises: d) positioning a retention ring (28) coaxial in radial superimposition around the semifinished product (S) previously wound on the building drum (13); e) engaging, against the retention ring (28), a radially outer annular layer (7a) formed by the shaped semifinishedproduct (S); f) retaining the radially outer annular layer (7a) against the retention ring (28), while the profiler drum (17) is radially contracted.

3. Process according to claim 1 or 2, wherein the action c) comprises switching the profiler drum (17) between a first operating condition, in which the radially outer expansion surface (19) of the profiler drum (17) has a maximum diameter smaller than or equal to a diameter of a deposition surface (14) presented externally by the building drum (13), and a second operating condition in which the expansion surface (19) radially projects through the annular opening (16).

4. Process according to one or more of the preceding claims, wherein at least one of said semifinished products (S) is made in strip form, circumferentially wound around the building drum (13).

5. Process according to one or more of the preceding claims, wherein before completing the action c), the semifinished product (S) has axially opposite terminal flaps arranged each around one of said half-drums (15).

6. Process according to one or more of the preceding claims, wherein the mutual moving away of the half-drums (15) progressively continues during the action c).

7. Process according to one or more of the preceding claims, wherein the mutually moving away of the half-drums (15) progressively continues during the action c), up to disengaging the semifinished product (S) simultaneous with a complete transfer of the semifinished product (S) on the profiler drum (17).

8. Process according to one or more of the preceding claims, comprising: making at least one radially outer annular layer (7a); making at least one radially inner annular layer (7b); coupling said at least one radially inner annular layer (7b) against a radially inner surface of a multilayer annular component (7) being processed comprising said at least one radially outer annular layer (7a).

9. Process according to claim 8, wherein the forming cycles comprise an initial forming cycle for making the radially outer annular layer (7a) and a final forming cycle for making the radially inner annular layer (7b).

10. Process according to claim 8 or 9, wherein coupling said at least one radially outer annular layer (7a) comprises, during the execution of the initial forming cycle: d) positioning a retention ring (28) coaxial in radial superimposition with respect to the semifinished product (S) wound on the building drum (13); e) engaging, against the retention ring (28), the radially outer annular layer (7a) formed by the shaped semifinished product (S); f) retaining the radially outer annular layer (7a) against the retention ring (28), while the profiler drum (17) is radially contracted.

11. Process according to one or more of the claims from 8 to 10, wherein coupling said at least one radially inner annular layer (7b) comprises, during the execution of the final forming cycle: d) coaxially positioning the retention ring (28) in radialsuperimposition with respect to the semifinished product (S) previously wound around the building drum (13); e) engaging, against the multilayer annular component (7) being processed borne by the retention ring (28), the radially inner annular layer (7b) formed by the shaped semifinished product (S).

12. Process according to one or more of the claims from 9 to 11, wherein the forming cycles also comprise at least one intermediate forming cycle in order to make at least one intermediate annular layer radially interposed between the radially outer annular layer (7a) and the radially inner annular layer (7b).

13. Process according to claim 12, also comprising coupling each intermediate layer against the radially inner surface of the multilayer annular component (7) being processed during the execution of the intermediate forming cycle, through: d) coaxially positioning the retention ring (28) in radial superimposition with respect to the semifinished product (S) wound around the building drum (13); e) engaging, against the multilayer annular component (7) being processed borne by the retention ring (28), the intermediate layer formed by the shaped semifinished product (S).

14. Process according to one or more of the preceding claims, also comprising, at the end of at least one of said forming cycles: radially contracting the profiler drum (17); axially approaching the half-drums (15) of the building drum (13).

15. Process according to one or more of the claims from 2 to 14, also comprising, at the end of at least one of said forming cycles: axially translating the retention ring (28), in order to place it in a waiting position axially displaced with respect to the profiler drum (17).

16. Process according to one or more of the claims from 8 to 15, also comprising, after coupling said at least one radially inner annular layer (7b): radially expanding the retention ring (28) in order to disengage it from the multilayer annular component (7) borne by the profiler drum (17); axially translating the retention ring (28) with respect to the profiler drum (17); transferring to a subsequent work station (37) the multilayer annular component (7) together with the profiler drum (17).

17. Process according to claim 16, wherein transferring to the subsequent work station (37) comprises: engaging the multilayer annular component (7) to a grip member (39); radially contracting the profiler drum (17) in order to disengage it from the multilayer annular component (7).

18. Process according to claim 16 or 17, also comprising, after transferring to the subsequent work station (37); repositioning the profiler drum (17) coaxial between the half-drums (15) of the building drum (13); mutually approaching the half-drums (15) of the building drum (13).

19. Process according to claim 16 or 17, also comprising, after transferring to the subsequent work station (37); positioning a further profiler drum (17) coaxial between the half-drums (15) of the building drum (13); mutually approaching the half-drums (15) of the building drum (13).

20. Process according to one or more of the claims from 8 to 19, also comprising, after coupling said at least one radially inner annular layer (7b): disengaging the profiler drum (17) from the multilayer annular component (7) borne by the retention ring (28); translating the retention ring (28) in order to transfer, to a subsequent work station (37), the multilayer annular component (7).

21. Apparatus for making multilayer annular components in building of tyres for vehicles, comprising: a substantially cylindrical building drum (13), comprising two half-drums (15) mutually aligned and movable along a rotation axis (X); wherein the building drum (13) is switchable between a deposition condition in which respective terminal edges axially facing each other of the half-drums (15) are mutually approached, and a shaping condition in which said terminal edges are mutually spaced; at least one feeder (36) configured for applying semifinished products (S) around a deposition surface (14) presented externally by the building drum (13) in the deposition condition; a profiler drum (17) situated coaxial within the buildingdrum (13), wherein the profiler drum (17) has an expansion surface (19) that is radially external and axially convex, wherein the profiler drum (17) is switchable between a first operating condition, in which the expansion surface (19) has a maximum diameter smaller or equal to a diameter of the deposition surface (14), and a second operating condition in which the expansion surface (19) radially projects through an annular opening (16) defined between said half-drums (15).

22. Apparatus according to claim 21, wherein in the second operating condition, the maximum diameter of the expansion surface (19) is greater than the diameter of the deposition surface (14).

23. Apparatus according to claim 21 or 22, also comprising a retention ring (28) positionable coaxial outside the building drum (13), in radial superimposition with respect to the profiler drum, and configured for engaging a multilayer annular component (7) being processed comprising at least one radially outer annular layer (7a).

24. Apparatus according to one or more of the claims from 21 to 23, wherein the building drum (13) is also switchable into an open condition in which the half-drums (15) are mutually moved away from each other to a greater extent with respect to the shaping condition, in order to allow disengagement of the profiler drum (17) from the building drum (13) through the annular opening (16).

25. Apparatus according to one or more of the claims from 21 to 24, wherein the expansion surface (19) of the profiler drum (17) has a curvilinear axial profile defining a convexitydirected towards a radially outer direction.

26. Apparatus according to one or more of the claims from 21 to 25, wherein the expansion surface (19) of the profiler drum (17) lacks through axial interruptions.

27. Apparatus according to one or more of the claims from21 to 26, wherein each half-drum (15) of the building drum (13) comprises a plurality of building sectors (15b) that are circumferentially distributed.

28. Apparatus according to claim 27 , wherein the building sectors (15b) of each half-drum (15) are radially movable in order to modulate an external diameter of the deposition surface (14).

29. Apparatus according to claim 27 or 28, wherein each half-drum (15) comprises a discoid flange (15a) carrying radial guide seats each slidably engaging one of the building sectors (15b).

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