Drum for manufacturing a tyre and associated method

Abstract

This manufacturing drum (2) comprises: - a shaft (4); - a body (6) mounted on the shaft (4) and provided with a central part (8) and with two end parts (10) arranged axially on either side of the central part (8) and provided with a groove (12) for receiving a bead wire of the tyre; and - two tubular membranes (14) which each cover a groove (12). Each tubular membrane (14) is elastically deformable between: - a first position in which the tubular membrane (14) is generally cylindrical in shape and remains radially at a distance from a bottom (16) of the groove (12) in question; and - a second position in which the tubular membrane (14) is deformed and is in contact with the bottom (16) of the groove (12) in question.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Tire manufacturing drum and associated process

[0003] technical field

[0004] The invention relates to the manufacture of tires.

[0005] In particular, the invention relates to a tire manufacturing drum comprising two tubular membranes each covering a groove for receiving a tire bead, and a method for manufacturing a tire carcass ply from carcass ply constituents and such a manufacturing drum.

[0006] Previous techniques

[0007] A tire is divided into three distinct zones including a crown which includes a crown reinforcement and a tread intended to come into contact with the ground, beads intended to ensure the grip of the tire on the rim of a wheel, and sidewalls intended to connect the crown to the beads.

[0008] To manufacture a tire, elements in the form of rods, strips or sheets are successively and circumferentially placed on a manufacturing drum to form a cylindrical tire blank.

[0009] The element of a tire blank that forms the carcass reinforcement of the tire is called the carcass ply. The carcass ply is also folded around the beads on this manufacturing drum. This manufacturing drum is generally called a finishing drum. Such a finishing drum is described in document EP 0 953 434 B l.

[0010] The strips or sheets must be laid on smooth surfaces. However, the rods are positioned in grooves in the manufacturing drum. These grooves create a recess that complicates the laying of the strips or sheets.

[0011] The invention aims to improve the application of strips or plies during the manufacture of a tire carcass plies. Description of the invention

[0012] The invention relates to a drum for manufacturing a tire carcass ply from carcass ply components, the drum comprising:

[0013] - a shaft extending axially;

[0014] - a body mounted on the barrel and equipped with a central part for receiving components of the carcass ply, and two end parts for receiving components of the carcass ply which are arranged axially on either side of the central part and which are each equipped with a groove for receiving a tire bead

[0015] According to a general characteristic, the manufacturing drum further comprises two tubular membranes, each covering at least the throat of one of the two end parts, each tubular membrane being elastically deformable between:

[0016] - a first position in which said tubular membrane is generally cylindrical in shape and remains radially distant from the bottom of the throat of the end portion concerned; and

[0017] - a second position in which said tubular membrane is deformed and is in contact with the bottom of the throat of the end part concerned.

[0018] The tubular membrane in the first position facilitates the placement of the carcass sheet components by providing a smooth surface for component placement.

[0019] The tubular membrane in the second position allows the carcass ply rods to enter the grooves of the end parts in order to perform a step of rolling the axial ends of the carcass ply around the rods.

[0020] Advantageously, the end parts are mobile in axial translation along the shaft.

[0021] Advantageously, the manufacturing drum includes lifting devices located at the axial ends of the drum body and configured to move radially outwards from the axial ends of the carcass layer constituents placed on the end parts of the drum body.

[0022] The lifting devices make it easier to roll up the axial ends of the carcass layer around the carcass layer rods.

[0023] Optionally the manufacturing drum includes two elastic sleeves which each extend axially from the central part of the drum body to one of the two tubular membranes, each elastic sleeve being arranged so that the surface jointly formed by the radially outer surface of the central part of the drum body, by the radially outer surface of the elastic sleeves and by the radially outer surface of the tubular membranes is axially continuous.

[0024] This creates an axially smooth and continuous surface between the tubular elastic membranes.

[0025] An "axially continuous" surface is understood to mean that this surface is continuous or that its only discontinuities are the junctions between its different adjacent constituents.

[0026] According to a first design, each tubular membrane is axially in contact with the elastic sleeve adj acent to said tubular membrane.

[0027] Optionally, according to the first design, each elastic sleeve is in contact with the central part of the drum body.

[0028] According to a second alternative design, each elastic sleeve was made of material with the tubular membrane adjacent to said elastic sleeve.

[0029] Advantageously, the manufacturing drum further includes an expansion device configured to move the drum body between a position radially close to the drum and at least one position radially far from the drum.

[0030] Preferably, each tubular membrane is in the first position when the constituents of the carcass ply cover it at least partially and the drum body is in the position radially close to the shell, each tubular membrane being in the second position when the constituents of the carcass ply cover it at least partially and the drum body is in the position radially far from the shell.

[0031] The drum body expansion device allows the components of the carcass ply deposited on the drum body to be put under tension.

[0032] Preferably, the central part and the two end parts of the drum body each comprise a plurality of sectors which are arranged circumferentially, the expansion device of the drum body comprising at least one inflatable expansion chamber located radially inside the sectors of the drum body, the drum body being in the radially distant position from the shell when said inflatable expansion chamber is inflated.

[0033] Optionally, the drum body expansion device further includes an expansion mechanism configured to move the drum body from the radially close position of the drum to a radially intermediate position located between the radially close and far positions of the drum.

[0034] By moving the drum body to the radially intermediate position, the expansion mechanism allows intermediate tensioning of the carcass sheet constituents, for example rubber strips and strips reinforced with textile and / or metallic threads, in order to facilitate their placement on the manufacturing drum.

[0035] According to a particular embodiment, the expansion mechanism includes surfaces inclined with respect to the axial direction which are axially mobile so as to convert their axial movement into a radial movement of the sectors of the drum body.

[0036] Advantageously, the central part of the drum body comprises a plurality of circumferentially juxtaposed plates, each plate extending longitudinally along the axial direction and comprising two serrated edges that are circumferentially opposed.

[0037] The serrated edges allow better continuity in the circumferential direction of the juxtaposed plates, in particular by reducing the number of sharp edges to which the carcass ply constituents deposited on the body of the manufacturing drum can be exposed, and thus reduce wear on the carcass ply constituents during their placement.

[0038] Advantageously, the radially external surfaces of the plates are free of visible screws.

[0039] Optionally, the radially outer surface of each plate includes a non-stick coating.

[0040] The anti-stick coating may include NUFLON® PPR01.

[0041] This facilitates the extraction of the carcass sheet from the manufacturing drum once the step of folding the axial ends of the carcass sheet around the rods has been completed.

[0042] The present invention also relates to a method for manufacturing a tire carcass ply from carcass ply components and a manufacturing drum as defined above, comprising:

[0043] - the placement of the carcass sheet component on the central part and on the end parts of the drum body;

[0044] - the elastic deformation of the tubular membranes from the first position to the second position so that rods constituting the frame are arranged in the grooves of the end parts of the drum body; and

[0045] - the folding of the axial ends of the constituents of the carcass sheet around each of the rods.

[0046] Optionally, the placement of the carcass sheet constituent on the central part and on the end parts of the drum body is carried out when the drum body is in the radially close position to the shell.

[0047] Optionally, the elastic deformation of the tubular membranes from the first position to the second position occurs spontaneously during the movement of the drum body to the position radially furthest from the drum. Optionally, the installation of the carcass ply component includes the application of rubber strips and strips reinforced with textile and / or metallic threads, and includes the movement of the drum body from the position radially closest to the drum to the radially intermediate position.

[0048] Brief description of the drawings

[0049] The present invention will be better understood upon study of the detailed description of an embodiment, taken by way of non-limiting example and illustrated by the accompanying drawings in which:

[0050] [Fig 1] is a longitudinal cross-sectional view of a manufacturing drum in a position radially close to a barrel according to an exemplary embodiment of the invention;

[0051] [Fig 2] and [Fig3] are detailed views of a tubular membrane and elastic sleeve of the manufacturing drum of figure 1;

[0052] [Fig 4] is a detail view of an expansion mechanism of the manufacturing drum of figure 1;

[0053] [Fig 5] is a detail view of plates from the central part of the body of the manufacturing drum in Figure 1;

[0054] [Fig 6] is a view of the manufacturing drum of figure 1 along axis VI-VI;

[0055] [Fig 7] is a view similar to Figure 1 when the manufacturing drum is in a position radially away from the barrel; and

[0056] [Fig 8] schematically illustrates a manufacturing process for a tire carcass ply according to an example of an embodiment of the invention.

[0057] Detailed description

[0058] Figure 1 shows a longitudinal section of a manufacturing drum 2 for a tire carcass ply made from carcass ply components, for example, from rubber strips and strips reinforced with textile and / or metallic threads. The manufacturing drum 2 is mounted on a frame (not shown) and comprises a barrel 4 extending axially from the frame along a longitudinal axis X-X', and a body 6, generally cylindrical, mounted on the barrel 4.

[0059] The body 6 of the manufacturing drum 2 comprises a central part 8 and two end parts 10 which are arranged axially on either side of the central part 8 of the body 6 and which are movable in axial translation along the barrel 4, the central part 8 of the body 6 being fixed in axial translation on the barrel 4. The outside diameter of the central part 8 of the body 6 is greater than the outside diameter of the end parts 10 of the body 6 so that the end parts 10 of the body 6 are able to move axially partly inside the central part 8 of the body 6.

[0060] The barrel 4 extends from the frame, on which the manufacturing drum 2 is mounted, and is free to rotate relative to the frame. The body 6 of the manufacturing drum 2 is fixed in rotation relative to the barrel 4.

[0061] The central portion 8 and the two end portions 10 of the body 6 are designed to receive the components of the carcass layer. In particular, the central portion 8 and the two end portions 10 of the body 6 each comprise a plurality of sectors 8a, 10a which are arranged circumferentially and which are designed to receive the components of the carcass layer.

[0062] Each end portion 10 of the body 6 is provided with a groove 12 for receiving a tire rod. In particular, each sector 10a of the considered end portion 10 of the body 6 is provided with the receiving groove 12.

[0063] Each end part 10 of the manufacturing drum 2 further includes a transmission part 10b of an axial motion which is located radially inside the sectors 10a of the end part 10 under consideration.

[0064] The manufacturing drum 2 comprises two tubular membranes 14, each covering at least the groove 12 of one of the two end portions 10 of the body 6. As illustrated more clearly in Figures 2 and 3, each tubular membrane 14 extends axially from the end of the associated end portion 10 of the body 6, which is located on the side of the central portion 8 of the body 6, axially along the groove 12 of the associated end portion 10 of the body 6, and beyond the groove 12 of the associated end portion 10 of the body 6. Each tubular membrane 14 is radially in contact with the associated end portion 10 of the manufacturing drum 2.

[0065] Each tubular membrane 14 is elastically deformable between a first position and a second position. In the first position (Figure 2), each tubular membrane 14 is generally cylindrical in shape and remains radially distant from a bottom 16 of the groove 12 of the associated end portion 10 of the body 6. In the first position, each tubular membrane 14 is radially in contact against the associated end portion 10 of the manufacturing drum 2 outside the portion remaining radially distant from a bottom 16 of the groove 12.

[0066] In the second position (figure 3), each tubular membrane 14 is deformed and is in contact with the bottom 16 of the groove 12 of the associated end part 10 of the body 6. Each tubular membrane 14 is deformed locally to come into contact with the bottom 16 of the groove 12, the rest of the membrane remaining radially in contact against the associated end part 10 of the manufacturing drum 2.

[0067] The manufacturing drum 2 also includes two elastic sleeves 18 which each extend axially from the central part 8 of the body 6 to one of the two tubular membranes 14.

[0068] The elastic sleeves 18 are arranged such that the surface jointly formed by the radially outer surface of the central portion 8 of the body 6, by the radially outer surface of the elastic sleeves 18, and by the radially outer surface of the tubular membranes 14 is axially continuous. In particular, each elastic sleeve 18 is axially in contact with the adjacent tubular membrane 14 and with the central portion 8 of the body 6. Each elastic sleeve 18 is thus a separate piece from the adjacent tubular membrane 14. Alternatively, each elastic sleeve 18 could be formed from the same material as the tubular membrane 14 adjacent to the associated elastic sleeve 18.

[0069] With reference to Figure 4, the manufacturing drum 2 further includes an expansion device 20 capable of moving the body 6 of the manufacturing drum 2 between a position radially close to the drum 4 and a position radially far from the drum 4.

[0070] The expansion device 20 of the body 6 of the manufacturing drum 2 comprises two inflatable expansion chambers 22 each located radially inside the sectors 10a and radially outside the axial motion transmission parts 10b of the end parts 10 of the body 6.

[0071] When the inflatable expansion chambers 22 are in an inflated state, the body 6 of the manufacturing drum 2 is in the position radially away from the drum 4. In particular, the inflatable expansion chambers 22 in the inflated state exert a force radially towards the sectors 10a of the end parts 10 of the body 6 which are connected to the sectors 8a of the central part 8 of the body 6 by rods 23 so that the sectors 10a of the end parts 10 and of the central part 8 of the body 6 are in the position radially away from the drum 4.

[0072] The expansion device 20 of the body 6 of the manufacturing drum 2 further includes an expansion mechanism 24 capable of moving the body 6 of the manufacturing drum 2 from the radially close position of the drum 4 to a radially intermediate position located radially between the radially close and distant positions of the drum 4. In particular, when the inflatable expansion chambers 22 are in a deflated state, the body 6 of the manufacturing drum 2 is in the radially close position of the drum 4, or in the radially intermediate position depending on the action of the expansion mechanism 24.

[0073] The expansion mechanism 24 comprises, axially on each side of the central portion 8 of the body 6, cylinders 25 and radially internal annular surfaces 26a that are inclined with respect to the axial direction. The sectors 10a of the end portions 10 each comprise a surface 26b that is inclined with respect to the axial direction and radially opposite the associated radially internal annular surface 26a.

[0074] Each cylinder 25 is equipped with a piston radially surrounding the axial motion transmission part 10b of the associated end portion 10 and with sealing gaskets. Each cylinder 25 is capable of driving the associated radially inner annular surface 26a in axial translation.Each radially internal inclined annular surface 26a is opposite the radially external inclined surfaces 26b of the sectors 10a of the associated end part 10 and is axially movable relative to the radially external inclined surfaces 26b of the sectors 10a of the associated end part so as to convert the axial movement of the radially internal inclined annular surface 26a considered into a radial movement of the radially external inclined surfaces 26b of the sectors 10a of the associated end part 10, for example by means of a roller disposed between the radially internal inclined annular surface 26a considered and each radially external inclined surface 26b of the sectors 10a of the associated end part 10.

[0075] With reference to figure 5, the central part 8 of the body 6 comprises a plurality of plates 28 juxtaposed circumferentially over the entire circumference of the central part 8 of the body and extending longitudinally between the two elastic sleeves 18.

[0076] The radially internal diameter of each plate 28 of the central part 8 of the body 6 is greater than the radially external diameter of the elastic sleeves 18.

[0077] Each plate 28 of the central part 8 of the body 6 comprises two serrated edges that are circumferentially opposed. In particular, each plate 28 of the central part 8 of the body 6 comprises two long edges that extend axially, forming teeth or undulations.

[0078] The radially outer surface of each plate 28 of the central part 8 of the body 6 includes an anti-stick coating. With reference to Figure 6, the manufacturing drum 2 comprises a ring 30 arranged around the barrel 4, and a plurality of connecting rods 32, each connected on one side to the ring 30 and on the other side to one of the rods 23. The connecting rods 32 guide the sectors 10a of the end parts 10 of the body 6 and the sectors 8a of the central part 8 of the body 6 when the body 6 of the manufacturing drum 2 moves between the radially close position of the barrel 4 and the radially far position of the barrel 4, thus ensuring the synchronization of the movement of the sectors 10a of the end parts 10 of the body 6 and the sectors 8a of the central part 8 of the body 6. When the body 6 of the manufacturing drum 2 is in the radially close position of the barrel 4, the connecting rods 32 are in a folded position.

[0079] With reference to Figure 7, when the inflatable expansion chambers 22 are in the inflated state, i.e. when the body 6 of the manufacturing drum 2 is in the position radially away from the barrel 4, the connecting rods 32 are in a deployed position.

[0080] The radial distance between the barrel 4 and the ends of the connecting rods 32 in the folded position which are connected to the rods 23 is less than the radial distance between the barrel 4 and the ends of the connecting rods 32 in the deployed position which are connected to the rods 23.

[0081] Figure 8 represents a process for manufacturing a tire carcass ply from carcass ply components and manufacturing drum 2.

[0082] We begin with a step SI of laying constituent of the carcass sheet on the central part 8 and on the end parts 10 of the body 6. In particular, we successively lay rubber strips and strips reinforced with textile and / or metallic threads on the central part 8 and on the end parts 10 of the body 6 when the body 6 of the manufacturing drum 2 is in the radially close position to the drum 4.

[0083] In order to improve the holding of the strips, the body 6 of the manufacturing drum 2 is also moved during step SI from the position radially close to the drum 4 to the radially intermediate position so that the strips already laid are tensioned before laying other strips.

[0084] During the SI step, rods constituting the carcass sheet are arranged opposite the grooves 12 of the end parts 10 of the body 6, for example by means of rod guides.

[0085] Then, during a step S2, the tubular membranes 14 are elastically deformed from the first position to the second position so that rods constituting the carcass sheet penetrate the grooves 12 of the end parts 10 of the body 6.

[0086] In particular, during step S2 the body 6 of the manufacturing drum 2 is moved from the radially intermediate position to the radially distant position of the drum 4 so that the tubular membranes 14 deform freely from the first position to the second position and the rods penetrate the grooves 12 of the end parts 10 of the body 6. More precisely, the inflatable expansion chambers 22 are inflated so that the sectors 10a of the end parts 10 and of the central part 8 of the body 6 are in the radially distant position of the drum 4.

[0087] Each tubular membrane 14 is therefore in the first position when the constituents of the carcass sheet cover it at least in part and the body 6 of the manufacturing drum 2 is in the position radially close to the drum 4 or in the radially intermediate position.

[0088] Each tubular membrane 14 is in the second position when the constituents of the carcass sheet cover it at least in part and the body 6 of the manufacturing drum 2 is in the position radially away from the barrel 4.

[0089] Finally, a step S3 is performed, involving folding, or turning, the axial ends of the constituents of the carcass sheet around each of the rods.

[0090] For example, the body 6 of the manufacturing drum 2 includes lifting devices (not shown) located at the axial ends of the body 6 of the manufacturing drum 2 and capable of radially moving outwards the axial ends of the constituents of the carcass layer placed on the end parts 10 of the body 6.

Claims

DEMANDS 1. Drum for manufacturing (2) a tire carcass ply from carcass ply constituents, the drum (2) comprising: - a shaft (4) extending axially; - a body (6) mounted on the barrel (4) and provided with a central part (8) for receiving components of the carcass ply, and two end parts (10) for receiving components of the carcass ply which are arranged axially on either side of the central part (8) and which are each provided with a groove (12) for receiving a tire rod; characterized in that it further comprises two tubular membranes (14) which each cover at least the groove (12) of one of the two end parts (10), each tubular membrane (14) being elastically deformable between: - a first position in which said tubular membrane (14) is generally cylindrical in shape and remains radially distant from a bottom (16) of the groove (12) of the end portion (10) concerned; and - a second position in which said tubular membrane (14) is deformed and is in contact with the bottom (16) of the groove (12) of the end part (10) concerned.

2. Manufacturing drum (2) according to claim 1, comprising two elastic sleeves (18) which each extend axially from the central part (8) of the body (6) of the drum (2) to one of the two tubular membranes (14), each elastic sleeve (18) being arranged so that the surface jointly formed by the radially outer surface of the central part (8) of the body (6) of the drum (2), by the radially outer surface of the elastic sleeves (18) and by the radially outer surface of the tubular membranes (14) is axially continuous.

3. Manufacturing drum (2) according to claim 2, in which each elastic sleeve (18) is made of material with the tubular membrane (14) adjacent to said elastic sleeve (18).

4. Drum manufactured (2) according to any one of claims 1 to 3, further comprising an expansion device (20) configured to move the body (6) of the drum (2) between a position radially close to the barrel (4) and at least one position radially far from the barrel (4), each tubular membrane (14) being in the first position when the constituents of the carcass ply cover it at least in part and the body (6) of the drum (2) is in the position radially close to the barrel (4), each tubular membrane (14) being in the second position when the constituents of the carcass ply cover it at least in part and the body (6) of the drum (2) is in the position radially far from the barrel (4).

5. A manufacturing drum (2) according to claim 4, wherein the central portion (8) and the two end portions (10) of the drum body (6) (2) each comprise a plurality of circumferentially arranged sectors (8a, 10a), the expansion device (20) of the drum body (6) (2) comprising at least one inflatable expansion chamber (22) located radially within the sectors (8a, 10a) of the drum body (6) (2), the drum body (6) (2) being in the radially distant position from the drum (4) when said inflatable expansion chamber (22) is inflated, the expansion device (20) of the drum body (6) (2) further comprising an expansion mechanism (24) configured to move the drum body (6) (2) from the radially close position to the drum (4) to a radially intermediate position located between the radially close and distant positions from the drum (4).

6. Manufacturing drum (2) according to claim 5, wherein the expansion mechanism (24) comprises inclined surfaces (26a) with respect to the axial direction which are axially movable so as to convert their axial movement into a radial movement of the sectors (8a, 10a) of the body (6) of the drum (2).

7. Drum manufactured (2) according to any one of claims 1 to 6, wherein the central part (8) of the body (6) of the drum (2) comprises a plurality of circumferentially juxtaposed plates (28), each plate (28) extending longitudinally along the axial direction and comprising two serrated edges which are circumferentially opposed.

8. Manufacturing drum (2) according to claim 7, wherein the radially outer surface of each plate (28) comprises an anti-stick coating.

9. A method for manufacturing a tire carcass ply from carcass ply components and a manufacturing drum (2) according to any one of claims 1 to 8, comprising: - the placement of the carcass sheet constituent on the central part (8) and on the end parts (10) of the body (6) of the drum (2); - the elastic deformation of the tubular membranes (14) from the first position to the second position so that rods constituting the carcass layer are arranged in the grooves (12) of the end parts (10) of the body (6) of the drum (2); and - the folding of the axial ends of the constituents of the carcass sheet around each of the rods.

10. A manufacturing method according to claim 9 dependent on at least claim 5, wherein the laying of the carcass ply constituent includes laying rubber strips and strips reinforced with textile and / or metallic threads, and includes moving the body (6) of the drum (2) from the position radially close to the barrel (4) to the radially intermediate position.

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