Apparatus for vulcanizing and moulding tyres and method for preheating circumferential sectors in apparatus for vulcanizing and moulding tyres

Abstract

An apparatus for vulcanizing and moulding a tyre comprises an annular container (16) engaged or configured to engage a plurality of circumferential sectors (10). The annular container (16) is movable between a raised position, in which the circumferential sectors (10) are circumferentially spaced apart from each other, and a lowered position, in which the annular container (16) surrounds the circumferential sectors (10) and the circumferential sectors (10) are moved circumferentially close to each other. A conduit (26) for circulating a heating medium is arranged in the annular container (16). The duct (26) surrounds the circumferential sector (10) and has a waveform pattern in which the duct runs towards the bottom (18) and towards the top (17).

Description

Technical Field

[0001] The present invention relates to the processing and equipment for manufacturing tires for vehicle wheels.

[0002] The production cycle of a tire for a vehicle wheel provides a building process in which various structural components of the tire itself can be manufactured and / or assembled on one or more drums to produce a green tire. The green tire is then transferred to a molding and vulcanization line where the molding and vulcanization process is actuated. The molding and vulcanization process is adapted to define the structure of the tire according to the desired geometry and tread design.

[0003] The present invention relates to an apparatus for vulcanizing and molding a tire and a method for preheating a circumferential sector in an apparatus for vulcanizing and molding a tire. The present invention particularly relates to the duct design of an apparatus for vulcanizing and molding a tire, the duct carrying a heating medium with which a mold containing a green tire to be molded and vulcanized is heated. Background Art

[0004] Components for vulcanizing and molding tires are known in the art.

[0005] Document US20090162460A1 provides a mold assembly including a plurality of segments arranged to form an annular ring when assembled together. A plurality of sliders surround the segments for receiving and supporting the segments. The sliders are slidable in a radial direction. The container housing further includes an annular actuating ring. The inner radial surface of the actuating ring is angled for engaging the outer angled surface of the slider. The tread mold segment has an outer radial surface having a channel for receiving a tubular member or an X-shaped connector for heating steam to pass through.

[0006] Document CN204196061U illustrates a steam chamber guide ring for a segmented tire mold. The steam chamber guide ring includes a guide ring body, a steam inlet, and a steam outlet. One or more steam circulation grooves are formed in the inner conical surface of the guide ring body. The steam circulation groove at the top is in communication with the steam inlet, the steam circulation groove at the bottom is in communication with the steam outlet, and steam circulation holes are provided between two adjacent steam circulation grooves.

[0007] Document JP2015155151A discloses a container for a tire vulcanizer. The container includes a cavity, and a steam pipe for supplying steam to the cavity is provided in the cavity. The steam pipe includes: a plurality of steam inlet ports to be connected to an external pipe for introducing steam; and a steam outlet port, and the introduced steam is discharged into the cavity from the steam outlet port. The container includes a steam discharge port, and the steam discharged into the cavity is discharged from the steam discharge port to the external pipe at a position symmetrical to the steam outlet port. A plurality of baffles are also installed in the cavity such that the steam introduced into the cavity meanders through the cavity.

[0008] Documents CN104690856, CN204820080U, and JP5036419B2 disclose additional mold assemblies for molding tires, and the additional mold assemblies include a container provided with an annular passage for steam.

[0009] Definition

[0010] Unless otherwise specified, "tire" refers to a green tire or a molded and vulcanized tire.

[0011] The terms "radial" and "axial" and the expressions "radially inner / outer" and "axially inner / outer" are used with reference to the radial direction of the equipment for vulcanizing and molding a tire or the tire to be vulcanized and molded within the equipment (i.e., with reference to the direction perpendicular to the geometric rotation axis of the equipment or the tire within the equipment, and the two axes substantially coincide), and the axial direction of the equipment and the tire (i.e., with reference to the direction parallel to the geometric rotation axis of the equipment or the tire within the equipment). The radial plane of a tire contains its rotation axis.

[0012] The terms "circumferential" and "circumferentially" are used with reference to the annular extension of the equipment and the tire within the equipment.

[0013] The expressions "low", "below", "lower", "bottom" and "high", "above", "upper", "top" are used to indicate the relative position with respect to the ground during the normal use of the reference element. Summary of the Invention

[0014] The applicant has observed that the above-mentioned prior art mold assemblies involve the following key aspects: the speed of instantaneous heating of the mold assembly, the heat distribution over the entire mold assembly, the cycle time, the setup time, the heat loss, and the steam consumption.

[0015] The applicant has observed that the segments of the mold are heated by heat conduction from the steam circulating through the annular ring to the segments. When the mold is closed and the annular ring surrounds the segments, the heat of the steam flowing through the pipes formed in the annular ring moves through the wall of the annular ring by conduction and then reaches the segments in contact with the radially inner surface of the annular ring.

[0016] The Applicant has observed that after each vulcanization and molding cycle, when the mold is opened to remove the vulcanized and molded tire and load the green tire to be vulcanized and molded by raising the annular ring and radially opening the segments, the segments cool down and once the annular ring is coupled to the segments again, the segments must be reheated by the annular ring again.

[0017] The Applicant has observed that the shape and position of the tube of the annular ring belonging to the prior art cannot heat the segments in an effective and rapid manner.

[0018] In particular, the Applicant has observed that the tube of the annular ring belonging to the prior art allows a reduced amount of heat to be transferred to the segments and this results in significant heat losses.

[0019] The Applicant has also observed that the tube of the annular ring belonging to the prior art does not allow a uniform distribution of heat to be provided to the segments and produces cold spots which can impair the efficiency and performance of the equipment and also possibly the quality of the tires manufactured.

[0020] The Applicant has observed that the above-mentioned drawbacks also have a negative impact on the set-up time (the time for heating the mold after loading and closing and before starting the vulcanization and molding cycle) as well as on the vulcanization and molding cycle time.

[0021] The Applicant has recognized the need to improve the heating efficiency of the segments and of the entire mold in the vulcanization and molding process in order to improve the quality of the tires, shorten the vulcanization and molding cycle time and reduce the power consumption.

[0022] The Applicant has recognized the need to solve the above-mentioned drawbacks by designing the steam tube inside the annular ring so as to maximize the heat transfer from the steam to the outer radial part of the circumferential sectors.

[0023] The Applicant has finally found that the above-mentioned object and other objects can be achieved by bringing the tube and the heating medium as close as possible to the circumferential sectors and widening as soon as possible the inner surface of the tube so as to cover most of the outer radial part of the circumferential sectors.

[0024] According to a first aspect, the present invention relates to an apparatus for vulcanizing and molding tires.

[0025] Preferably, the apparatus for vulcanizing and molding tires comprises a plurality of circumferential sectors arranged around a central axis, the plurality of circumferential sectors being movable between a first position and a second position, in which first position the plurality of circumferential sectors are circumferentially spaced apart from each other and away from the central axis, and in which second position the plurality of circumferential sectors move circumferentially closer to each other and closer to the central axis.

[0026] Preferably, the apparatus for vulcanizing and molding a tire comprises an annular container having a top, a bottom, a radially inner face and a radially outer face; the annular container is engaged with or configured to engage with a circumferential sector, and the annular container is movable between a raised position and a lowered position. In the raised position, the circumferential sector is in a first position, and in the lowered position, the annular container surrounds the circumferential sector and the circumferential sector is in a second position; wherein, in the lowered position, the radially inner face of the annular container contacts the radially outer portion of the circumferential sector.

[0027] Preferably, when the annular container is in the lowered position and the circumferential sector is in the second position, the apparatus defines a vulcanizing and molding cavity for receiving a tire.

[0028] Preferably, a conduit for circulating a heating medium is provided in the annular container, and when the annular container is in the lowered position, the conduit surrounds the circumferential sector.

[0029] Preferably, the conduit extends towards the bottom and towards the top in a waveform pattern.

[0030] According to a second aspect, the present invention relates to a method for preheating a circumferential sector in an apparatus for vulcanizing and molding a tire.

[0031] Preferably, the method comprises: providing an annular container which is placed to surround or configured to be placed to surround a plurality of circumferential sectors arranged around a central axis, and the plurality of circumferential sectors define a vulcanizing and molding cavity.

[0032] Preferably, the method comprises: causing a heating medium to flow through a waveform portion formed in the annular container, and the waveform portion extends from the top of the annular container to the bottom and from the bottom to the top.

[0033] Preferably, the radially inner face of the annular container contacts or is configured to be placed in contact with the radially outer portion of the circumferential sector.

[0034] Preferably, the apparatus is the apparatus in the first aspect.

[0035] The applicant believes that the present invention allows the above object to be achieved.

[0036] The applicant believes that, compared with the content disclosed in the cited references, the present invention achieves a more uniform temperature distribution (i.e., fewer cold spots) over the entire annular container.

[0037] The applicant also believes that the assembly including the annular container and the circumferential sector of the present invention reaches a temperature steady state more quickly than the assembly disclosed in the cited references.

[0038] The Applicant also believes that the present invention allows for a reduction in heat loss and steam consumption and thus allows for a reduction in energy consumption relative to the disclosure in the cited references.

[0039] The Applicant also believes that the present invention allows for a shortening of the vulcanization and molding cycle times and a shortening of the set-up time.

[0040] The present invention may have one or more of the preferred features described below.

[0041] Preferably, the heating medium is steam, preferably water steam.

[0042] Preferably, in the diametrical section of the annular container, at least some portions of the conduit are closer to the radial inner face of the annular container than to the radial outer face of the annular container.

[0043] Preferably, it is provided that the heating medium flows closer to the radial inner face of the annular container than to the radial outer face of the annular container.

[0044] Preferably, the annular container includes a discharge channel connected to the conduit.

[0045] Preferably, it is provided that the condensed portion of the steam is discharged from the corrugated profile or from the conduit.

[0046] Preferably, the discharge is carried out while the steam is flowing through the corrugated profile or the conduit.

[0047] The Applicant has verified that the discharge channel allows for the removal of the condensed portion of the steam and makes the steam drier and this improves the heat transfer capacity. In fact, the steam dryness directly affects the total amount of transferable energy contained in the steam, which affects the heating efficiency and quality. Supplying steam as close to dry as possible enables a higher heating efficiency.

[0048] Preferably, the discharge channel is annular and surrounds the central axis.

[0049] Preferably, the discharge channel is located below the conduit.

[0050] Preferably, the annular container includes at least one discharge hole connecting the conduit to the discharge channel.

[0051] Preferably, the conduit includes a plurality of top portions and a plurality of bottom portions following one another in an alternating manner.

[0052] Preferably, the discharge channel is connected to at least one of the bottom portions.

[0053] Preferably, the discharge channel is connected to all of the bottom portions.

[0054] Preferably, the discharge hole includes a radial portion and an axial portion.

[0055] Preferably, the discharge channel is connected to the outlet opening to discharge condensate.

[0056] The applicant has confirmed that by connecting the discharge channel to one or all of the bottom portions, it helps to discharge the condensate that tends to drip and settle downward.

[0057] Preferably, the annular container includes a ring connected to the bottom of the annular container, and the ring has a groove defining the discharge channel.

[0058] Preferably, the ring follows the circumferential profile of the annular container.

[0059] Preferably, each of the portions of the conduit has a flat shape.

[0060] Preferably, two dimensions of each of the portions of the conduit are much larger than the third dimension.

[0061] Preferably, the third dimension is perpendicular to the radial inner surface of the annular container.

[0062] Preferably, each of the portions is defined by a first inner surface parallel to the radial inner surface of the annular container, a second inner surface facing the first inner surface, and an edge inner surface connecting the first inner surface and the second inner surface.

[0063] Preferably, the first inner surface and the second inner surface are parallel to each other.

[0064] Preferably, the first inner surface and the second inner surface are identical to each other.

[0065] Preferably, the first inner surface is farther from the radial inner surface of the annular container than the second inner surface.

[0066] Preferably, the ratio “A1 / g” of the area “A1” of the first inner surface to the gap “g” between the first inner surface and the second inner surface is equal to or greater than 1000 mm.

[0067] Preferably, the ratio “A1 / g” of the area “A1” of the first inner surface to the gap “g” between the first inner surface and the second inner surface is equal to or less than 2000 mm.

[0068] Preferably, the ratio “A1 / C” of the area “A1” of the first inner surface to the width “C” of the vulcanization and molding cavity is equal to or greater than 80 mm.

[0069] Preferably, the ratio “A1 / C” of the area “A1” of the first inner surface to the width “C” of the vulcanization and molding cavity is equal to or less than 100 mm.

[0070] Preferably, the ratio "A1 / d1" of the area "A1" of the first inner surface to the first distance "d1" from the first inner surface to the radial inner surface of the annular container is equal to or greater than 1000 mm.

[0071] Preferably, the ratio "A1 / d1" of the area "A1" of the first inner surface to the first distance "d1" from the first inner surface to the radial inner surface of the annular container is equal to or less than 2000 mm.

[0072] Preferably, the first distance "d1" is measured perpendicular to the first inner surface.

[0073] Preferably, the ratio "A1 / d2" of the area "A1" of the first inner surface to the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container is equal to or greater than 100 mm.

[0074] Preferably, the ratio "A1 / d2" of the area "A1" of the first inner surface to the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container is equal to or less than 200 mm.

[0075] Preferably, the ratio "D / d2" of the maximum inner diameter "D" of the vulcanization and molding cavity to the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container is equal to or greater than 10 mm.

[0076] Preferably, the ratio "D / d2" of the maximum inner diameter "D" of the vulcanization and molding cavity to the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container is equal to or less than 20 mm.

[0077] Preferably, the ratio "d2 / d1" of the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container to the first distance "d1" from the first inner surface to the radial inner surface of the annular container is equal to or greater than 5.

[0078] Preferably, the ratio "d2 / d1" of the minimum radial distance "d2" from the second inner surface to the radial outer surface of the annular container to the first distance "d1" from the first inner surface to the radial inner surface of the annular container is equal to or less than 20.

[0079] Preferably, the ratio "h / C" of the height "h" of the first inner surface to the width "C" of the vulcanization and molding cavity is equal to or greater than 0.7.

[0080] Preferably, the ratio "h / C" of the height "h" of the first inner surface to the width "C" of the vulcanization and molding cavity is equal to or less than 0.9.

[0081] Preferably, the height "h" is measured in the diametrical section of the annular container and parallel to the first inner surface.

[0082] Preferably, the ratio "w / C" of the width "w" of the first inner surface to the width "C" of the vulcanization and molding cavity is equal to or greater than 0.4.

[0083] Preferably, the ratio "w / C" of the width "w" of the first inner surface to the width "C" of the vulcanization and molding cavity is equal to or less than 0.6.

[0084] Preferably, the width "w" is measured in the circumferential direction of the annular container.

[0085] Preferably, when observed in the radial direction, each of the portions is a U-shaped section of the conduit.

[0086] Preferably, the lower bend of the U-shaped section is one of the bottom portions of the conduit.

[0087] Preferably, each of the two upper end portions of the U-shaped section is connected to an adjacent U-shaped section through one of the top portions.

[0088] Preferably, each top portion includes a connection hole, one end of which is connected to the upper end portion of one of the U-shaped sections, and the other end of which is connected to the upper end portion of the other U-shaped section.

[0089] Preferably, each of the portions of the conduit is defined by a groove formed in one of the radial inner surfaces of the annular container.

[0090] Preferably, each of the portions of the conduit is defined by a plate that closes the groove.

[0091] Preferably, the first distance "d1" is the thickness of the plate.

[0092] Preferably, the radial inner working surface of the plate defines a part of the inner surface of the annular container.

[0093] Preferably, the radial inner working surface of the plate is flush with the rest of the inner surface of the annular container.

[0094] Preferably, each plate has a rectangular or trapezoidal profile.

[0095] Preferably, in the lowered position, the plate engages with the radially outer portion of the circumferential sector.

[0096] Preferably, the plate is made of a material with a thermal conductivity between 100 W / (m*K) and 180 W / (m*K).

[0097] Preferably, the plate is made of a material with a hardness between 40 HB and 210 HB.

[0098] Preferably, the plate is made of a material selected from the group consisting of brass or an alloy comprising copper, nickel, and silicon or an alloy comprising copper, tin, zinc, and lead.

[0099] Preferably, when the annular container is in the lowered position, each circumferential sector is coupled to a plurality of said portions.

[0100] Preferably, the conduit has an inlet and an outlet.

[0101] Preferably, the inlet and the outlet are formed on a radially outer face of the annular container.

[0102] Preferably, the inlet and the outlet are close to each other.

[0103] Preferably, the radially inner face of the annular container has a frustoconical shape.

[0104] Preferably, the plate is disposed on the radially inner face of the annular container.

[0105] Preferably, the radially outer portion of the circumferential sector is disposed on a virtual frustoconical surface.

[0106] Preferably, the average velocity of the heating medium in the corrugated pattern portion or in the conduit is between 15 m / s and 25 m / s, optionally 20 m / s.

[0107] Preferably, the flow rate of the heating medium through the corrugated pattern portion or through the conduit is between 4 m 3 / s and 8 m 3 / s.

[0108] Preferably, the annular container is made of structural steel.

[0109] Preferably, the ring is made of structural steel.

[0110] Preferably, the circumferential sectors are carried by the annular container.

[0111] Preferably, the annular container includes a plurality of guides positioned on the radially inner face, and the circumferential sectors are coupled to the guides so as to slide along the guides.

[0112] Preferably, each guide is placed between two adjacent plates.

[0113] Preferably, when the annular container moves between the raised position and the lowered position, the circumferential sectors slide between a first position and a second position along the guides.

[0114] Preferably, each of the circumferential sectors includes a support block and a working section.

[0115] Preferably, the working section is positioned radially inward relative to the support block.

[0116] Preferably, the support block includes a radially outer portion.

[0117] Preferably, the support block slides between a first position and a second position along the guide.

[0118] Preferably, the working section is mounted on the support block.

[0119] Preferably, the working section includes a working surface configured to engage a tire placed in a vulcanization and molding cavity.

[0120] Preferably, the surface is configured to engage a radially outer portion of the tire.

[0121] Preferably, each working section is removably connected to a corresponding support block such that the working section can be replaced by another working section.

[0122] Preferably, when the working section is mounted on the corresponding support block, the working section and the support block are integral with each other and move together between a first position and a second position.

[0123] Preferably, the apparatus further includes axially opposed first and second sidewall plates, each of the first and second sidewall plates having a working surface arranged to operate on a bead and a sidewall of a pair of tires.

[0124] Further features and advantages will become more apparent from a detailed description of preferred but non-exclusive embodiments of an apparatus for vulcanizing and molding a tire according to the present invention and a method for preheating a circumferential sector in an apparatus for vulcanizing and molding a tire. BRIEF DESCRIPTION OF THE DRAWINGS

[0125] Such a description will be made hereinafter with reference to the drawings, which are provided only as non-limiting examples, wherein:

[0126] - Figure 1 A vulcanization mold belonging to an apparatus for vulcanizing and molding a tire according to the present invention is shown in a diametrical cross-section;

[0127] - Figure 2 is Figure 1 a 3D view of an element of the apparatus, where some components are transparent to better show other components;

[0128] - Figure 3 is Figure 2 an enlarged portion of an element of the apparatus, where some components are removed;

[0129] - Figure 4 shows Figure 1 a 3D view of a part of the apparatus;

[0130] - Figure 5 showsFigure 2 The steam flow path inside the component;

[0131] - Figure 6 Is a diametrical cross - sectional view of a part of the device in the aforementioned figure;

[0132] - Figure 7 Is a sectional part of the device in the aforementioned figure;

[0133] - Figure 8 Is a different sectional part of the device in the aforementioned figure;

[0134] - Figure 9 Is another different sectional part of the device in the aforementioned figure;

[0135] - Figure 10 Is a graph showing the temperature - time development related to the device of the present invention and the devices of the prior art. Detailed Description

[0136] In Figure 1 is shown a diametrical cross - section of a vulcanization mold 1 belonging to a device for vulcanizing and molding a tire 2.

[0137] Figure 1 The tire 2 is shown only schematically and the tire mainly includes a carcass structure having one or more carcass plies. An impermeable elastomeric material layer or a so - called "liner" is applied inside the one or more carcass plies. Two anchoring annular structures are joined to the respective end flaps of the one or more carcass plies, each of said anchoring annular structures including a so - called bead core which bears an elastomeric filler in a radially outer position. The anchoring annular structures are integrated in the vicinity of the area generally identified by the "bead" 3, where the engagement between the tire and the corresponding mounting rim generally takes place. A belt structure including belt plies is circumferentially applied around the one or more carcass plies, and a tread 4 is circumferentially superimposed on the belt structure. Two sidewalls 5 are applied in laterally opposite positions of the one or more carcass plies, each of said sidewalls extending from the corresponding bead 3 to the corresponding lateral edge of the tread 4.

[0138] The vulcanization mold 1 includes a lower part 6 and an upper part 7 which can be interconnected.

[0139] The lower part 6 includes a first side wall plate 8, and the upper part 7 includes a second side wall plate 9. The first side wall plate 8 and the second side wall plate 9 are axially opposed. Each of the first side wall plate 8 and the second side wall plate 9 includes a working surface arranged to operate on the bead 3 and the side wall 5 of the green tire 2. The lower part 6 and the upper part 7 are axially movable between a first position in which the lower part and the upper part are spaced apart from each other, and a second position in which the lower part and the upper part are coupled to each other.

[0140] The vulcanization mold 1 includes a circumferential portion defined by a plurality of circumferential sectors 10, all of the circumferential sectors being arranged around the central axis "Y-Y" of the vulcanization mold 1. The circumferential sectors 10 are movable between a first position in which the circumferential sectors are circumferentially spaced apart from each other and away from the central axis "Y-Y", and a second position in which the circumferential sectors move circumferentially closer to each other and closer to the central axis "Y-Y". In the second position, the circumferential sectors 10, together with the first side wall plate 8 and the second side wall plate 9, define a vulcanization and molding cavity 11 for receiving the tire 2 ( Figure 6 ). The shape of the vulcanization and molding cavity 11 corresponds to the external shape imparted to the tire 2 after molding and vulcanization.

[0141] In the non-limiting example shown in the drawings, each circumferential sector 10 includes a support block 12 and a working section 13 ( Figure 1 and 6 ). The working section 13 is radially positioned inside the corresponding support block 12 with respect to the central axis "Y-Y" and is mounted on the corresponding support block 12 by connection means (not shown), which allows the working section 13 to be detached and replaced with another working section 13. In this way, the working section 13 can be replaced to vulcanize and mold tires having different sizes and / or different shapes and / or different tread patterns.

[0142] When the working section 13 is mounted on the corresponding support block 12, the working section 13 and the support block 12 are integral with each other and move together between the first position and the second position.

[0143] In other embodiments (not shown), each circumferential sector 10 may be made of only one piece.

[0144] Each working section 13 includes a working surface 14 ( Figure 1 and 6 ), which faces radially inwards towards the central axis "Y-Y" and is configured to engage the radial outer portion of the tire 2 when the tire 2 is placed in the vulcanization and molding cavity 11. In the second position, the mutually approaching working surfaces of the circumferential sectors 10 define a circumferential surface arranged to operate against the tread band 4 of the green tire 2 to be vulcanized.

[0145] In the non-limiting embodiment shown in the figure, the circumferential sector 10 is carried by the upper part 7. In particular, the circumferential sector 10 is mounted on a guide 15 belonging to the upper part 7 and is configured to move between a first position and a second position.

[0146] In fact, the upper part 7 includes an annular container 16 having a top 17, a bottom 18, a radially inner face 19 and a radially outer face 20. The annular container 16 is coaxial with the central axis "Y - Y" and carries the circumferential sector 10. The guide 15 is positioned on the radially inner face 19 and is formed as a T-shaped rib that slidably engages in a corresponding T-shaped groove 21 made in the radially outer part 22 of the circumferential sector 10 ( Figure 7 )

[0147] The radially outer part 22 of the circumferential sector 10 is arranged on a virtual frustoconical surface, and the radially inner face 19 of the annular container 16 has a frustoconical shape. Both the virtual frustoconical surface and the radially inner face 19 taper upwards, and the T-shaped rib and the T-shaped groove 21 are inclined and converge towards the central axis "Y - Y".

[0148] The annular container 16 is movable between a raised position and a lowered position. When the annular container 16 moves between the raised position and the lowered position, the guide 15 slides within the groove 21.

[0149] In the raised position, the circumferential sector 10 is in the first position, the annular container 16 is located above the circumferential sector 10, and the circumferential sector 10 is suspended from the annular container 16.

[0150] In the lowered position, the annular container 16 surrounds the circumferential sector 10, the circumferential sector 10 is in the second position, and the radially inner face 19 of the annular container 16 is in contact with the radially outer part 22 of the circumferential sector 10 ( Figure 1 and 6 ) In the lowered position, the circumferential sector is in the second position, and the device defines a vulcanization and molding cavity 11.

[0151] Means, known per se and not shown, are configured to move the above-mentioned components of the device between the above-mentioned positions.

[0152] A flexible and elastic membrane 23 (for example made of a composite based on butyl rubber) is mounted on the mold 1. The elastic membrane 23 has a pair of radially inner peripheries 24 provided with anchoring attachments that are anchored to a part of the device, such as Figure 1as shown, and internally defines an inflatable chamber 25. A generator and / or tank of hot pressurized fluid (not shown as it is of a known type) is operatively connected to the inflatable chamber 25 to inflate the elastic membrane 23. A vacuum pump (not shown as it is of a known type) is operatively connected or connectable to the inflatable chamber 25 to make the pressure inside the inflatable chamber 25 lower than the pressure outside the inflatable chamber 25 and to collapse / contract the membrane 23.

[0153] The device further includes means that are operatively associated with the vulcanization and molding cavity 11 and configured to also apply heat to the tire 2 received in the vulcanization and molding cavity 11 by hot pressurized fluid.

[0154] To preheat the circumferential sector 10 just before the vulcanization and molding step and also to heat the circumferential sector 10 during the vulcanization and molding step, a conduit 26 for circulating a heating medium is provided in the annular container 16. When the annular container 16 is in the lowered position, the conduit 26 surrounds the circumferential sector 10 and has a wavy pattern extending from the top 17 to the bottom 18 of the annular container 16 and from the bottom 18 to the top 17.

[0155] In the diametrical section of the annular container 16 ( Figure 1 、 5 、6 and 7), some portions 27 of the conduit 26 are closer to the radial inner face 19 of the annular container 16 than to the radial outer face 20 of the annular container 16.

[0156] In the non-limiting embodiment of the drawings, each of these portions 27 is flat and defined by a corresponding U-shaped section. Two dimensions of the U-shaped section are much larger than the third dimension, and the third dimension is perpendicular to the radial inner face 19 of the annular container 16. As Figure 3 shown, each of the U-shaped sections is a groove or recess formed in the radial inner face 19 of the annular container 16. The groove can be milled in the annular container 16. The groove is closed by a rectangular or trapezoidal plate 28 (removed in Figure 3 ). The radial inner working surface of the plate 28 defines a part of the inner face 19 of the annular container 16 and is flush with the rest of the inner face 19 of the annular container 16. As Figure 7 shown, each guide 15 is placed between two adjacent plates 28.

[0157] The annular container 16 is made of structural steel (e.g., non-alloy structural steel) and the plate 28 is made of a material having a thermal conductivity between 100 W / (m*K) and 180 W / (m*K) and a hardness between 40 HB and 210 HB. For example, the plate 28 is made of brass or an alloy containing copper, nickel, and silicon (such as CuNi2Si) or an alloy containing copper, tin, zinc, and lead (such as CuSn7Zn4Pb7). The plate 28 allows heat to be transferred from the heating medium to the circumferential sector 10.

[0158] Each U-shaped section includes a lower bend and two upper ends which are connected by two straight sections ( Figure 3 ). Each of the two upper ends of the U-shaped section is connected to an adjacent U-shaped section through a connecting hole 29, one end of the connecting hole being connected to the upper end of one of the U-shaped sections and the other end being connected to the upper end of the other U-shaped section. In Figure 7 the connecting hole 29 is formed through the thickness of the annular container 16. As Figure 5 shown, the waveform pattern of the conduit 26 includes a series of U-shaped sections and connecting holes 29 which follow each other in an alternating manner starting from the inlet 30 and terminating at the outlet 31. In other words, the conduit 26 includes a plurality of top portions and a plurality of bottom portions which follow each other in an alternating manner. The top portions are defined by the connecting holes 29, the bottom portions are defined by the lower bends of the U-shaped sections, and the top portions and the bottom portions are connected by the straight sections of the U-shaped sections. The inlet 30 and the outlet 31 are formed on the radial outer surface 20 of the annular container 16 and are close to each other ( Figure 2 、 5 and 7).

[0159] As Figure 3 、and Figure 6 shown in the diametrical section, each U-shaped section is defined by a first inner surface 32 parallel to the radial inner surface 19 of the annular container 16, a second inner surface 33 facing the first inner surface 32, and an edge inner surface 34 connecting the first inner surface 32 and the second inner surface 33. In the illustrated embodiment, each of the first inner surface 32 and the second inner surface 33 is U-shaped. The first inner surface 32 and the second inner surface 33 are parallel to each other and identical to each other. The first inner surface 32 is farther from the radial inner surface 19 of the annular container 16 than the second inner surface 33. In the illustrated embodiment, the second inner surface 33 is part of the corresponding plate 28.

[0160] The first inner surface 32 and the second inner surface 33 are spaced apart by a gap "g" (measured perpendicular to the first inner surface 32 and the second inner surface 33). The first distance "d1" from the second inner surface 33 to the radial inner surface 19 of the annular container 16 (measured perpendicular to the first inner surface 32 and the second inner surface 33) is the thickness of the plate 28. The area "A1" of the first inner surface 32 is equal to the area of the second inner surface 33. The first inner surface 32 has a height "h", which is measured parallel to the first inner surface 32 and in the diametrical section of the annular container 16 ( Figure 3 and 6 ). The first inner surface 32 has a width "w", which is measured parallel to the first inner surface 32 or along the circumferential direction of the annular container 16 and orthogonal to the height "h" ( Figure 3 and Figure 6 ). The first inner surface 32 is spaced apart from the radial outer surface 20 of the annular container 16 by a minimum radial distance "d2". The conduit 26 has an average cross-sectional area, which is measured perpendicular to the average flow direction of the heating medium inside the conduit 26. The vulcanization and molding cavity 11 has a maximum inner diameter "D" and a width "C" ( Figure 1 ).

[0161] The dimensions of the part 27 and related components can be determined as follows. The ratio "A1 / g" of the area "A1" of the first inner surface 32 to the gap "g" is between 1000 mm and 2000 mm. The ratio "A1 / C" of the area "A1" of the first inner surface 32 to the width "C" of the vulcanization and molding cavity 11 is between 80 mm and 100 mm. The ratio "A1 / d1" of the area "A1" of the first inner surface 32 to the first distance "d1" is between 1000 mm and 2000 mm. The ratio "A1 / d2" of the area "A1" of the first inner surface 32 to the minimum radial distance "d2" is between 100 mm and 200 mm. The ratio "D / d2" of the maximum inner diameter "D" of the vulcanization and molding cavity 11 to the minimum radial distance "d2" is between 10 mm and 20 mm. The ratio "d2 / d1" of the minimum radial distance "d2" to the first distance "d1" is between 5 and 20. The ratio "h / C" of the height "h" of the first inner surface 32 to the width "C" of the vulcanization and molding cavity 11 is between 0.7 and 0.9. The ratio "w / C" of the width "w" of the first inner surface 32 to the width "C" of the vulcanization and molding cavity 11 is between 0.4 and 0.6.

[0162] Due to the above dimensions, the average velocity of the heating medium in the conduit 26 can be limited to 15 m / s to 25 m / s, optionally 20 m / s, and the flow rate of the heating medium passing through the conduit can be limited to 4 m 3 / s and 8 m 3 / s.

[0163] The annular container 16 of the vulcanization mold 1 further includes a ring 35 connected to the bottom 18 of the annular container 16 to define the bottom 18. The ring 35 can be made of structural steel (e.g., non-alloy structural steel), which follows the circumferential contour of the annular container 16 and has a groove formed in its upper part. The groove of the ring 35 and the bottom 18 of the annular container 16 together define an annular discharge passage 36, which surrounds the central axis "Y - Y" and is positioned below the conduit 26. Figure 1 、 Figure 6 、 Figure 8 and Figure 9 shows a cross-section of the ring 35 and the discharge passage 36.

[0164] A plurality of discharge holes 37 connect the lower bent portion of the U-shaped section to the discharge passage 36. Figure 8 The shown discharge passage 36 includes a radial portion 38 connected to the lower bent portion and an axial portion 39 that connects the radial portion 38 to the discharge passage 36. An outlet opening 40 in the ring 35 allows the discharge of condensate from the discharge passage 36 ( Figure 8 and 9 ).

[0165] The annular container 16 can also be provided with a heat insulation layer 41 applied to its radially outer surface 20 ( Figure 1 and Figure 6 ).

[0166] In use, the green tire 2 is placed in the open vulcanization mold 1 while the circumferential sector 10 is in the first position and the annular container 16 is in the raised position. Then the vulcanization mold 1 is closed by lowering the annular container 16 and bringing the circumferential sector 10 to the second position. In the lowered position of the annular container 16, the plate 28 engages with the radially outer portion 22 of the circumferential sector 10, and each circumferential sector 10 is coupled to a pair of the U-shaped sections.

[0167] According to the preheating method of the method according to the present invention, a source of heating medium (e.g., steam, preferably water vapor) is connected to the conduit 26, and the steam circulates within the conduit 26. When the steam passes through the U-shaped section, the steam flows close to the circumferential sector 10. The heat of the steam is transferred from the U-shaped section to the circumferential sector 10 through the plate 28 and heats the circumferential sector 10. The condensed portion of the steam is discharged from the conduit 26 through the discharge holes 37 and the annular discharge passage 36 and exits the discharge passage 36 through the outlet opening 40.

[0168] Figure 10The figure shows the variation curve of the temperature T (°C) of the support block 12 of the circumferential sector 10 of the device of the present invention (line A) and the device according to the prior art (line B) with time t (min). Similar to the present invention, the annular container of the prior art is provided with a conduit formed in the wall and close to the radial outer surface of the annular container. Different from the present invention, the conduit of the prior art is a single annular conduit, and it is closer to the radial outer surface of the annular container than to the radial inner surface. <*

[0169] The parameters in Table 1 below apply to the device of the present invention (line A) and the device according to the prior art (line B). The parameters in Table 2 refer to the device of the present invention (line A). The parameters in Table 3 refer to the device of the prior art (line B).

[0170] Table 1

[0171] Table 2

[0172] Table 3

[0173] Figure 10 It shows that the circumferential sector 10 of the device according to the prior art (B) reaches the final constant temperature (180 °C) in 30 minutes, while the circumferential sector 10 of the device of the present invention (A) reaches the final temperature (185 °C) only in 13 minutes.

[0174] Table 4 below shows the calculated simulated steam consumption of the device of the present invention and the device according to the prior art to reach their respective stable temperatures. The steam consumption is reduced by about 57%.

[0175] Table 4

Claims

1. An apparatus for vulcanizing and molding a tire, the apparatus comprising: A plurality of circumferential sectors (10) arranged around a central axis (Y-Y), the plurality of circumferential sectors being movable between a first position and a second position, in the first position, the plurality of circumferential sectors being circumferentially spaced apart from each other and away from the central axis (Y-Y), in the second position, the plurality of circumferential sectors (10) moving circumferentially closer to each other and closer to the central axis (Y-Y); An annular container (16) having a top (17), a bottom (18), a radially inner face (19) and a radially outer face (20); the annular container (16) being engaged with or configured to be engaged with the circumferential sectors (10), the annular container (16) being movable between a raised position and a lowered position, in the raised position, the circumferential sectors (10) being in the first position, in the lowered position, the annular container (16) surrounding the circumferential sectors (10) and the circumferential sectors (10) being in the second position; wherein, in the lowered position, the radially inner face (19) of the annular container (16) contacts the radially outer portion (22) of the circumferential sectors (10); Wherein, when the annular container (16) is in the lowered position and the circumferential sectors (10) are in the second position, the apparatus defines a vulcanizing and molding cavity (11) for receiving a tire (2); Wherein a conduit (26) for circulating a heating medium is provided in the annular container (16), and when the annular container (16) is in the lowered position, the conduit (26) surrounds the circumferential sectors (10); Wherein the conduit (26) extends in a wavy pattern towards the bottom (18) and towards the top (17).

2. The device according to claim 1, wherein In a diametrical section of the annular container (16), at least some portions (27) of the conduit (26) are closer to the radially inner face (19) of the annular container (16) than to the radially outer face (20) of the annular container.

3. The device according to claim 1 or 2, wherein The annular container (16) includes a discharge channel (36) connected to the conduit (26).

4. The apparatus according to claim 3, wherein The discharge channel (36) is annular and surrounds the central axis (Y-Y).

5. The apparatus according to claim 3 or 4, wherein, The discharge channel (36) is positioned below the conduit (26).

6. The device according to one of claims 3 to 5, wherein, The annular container (16) includes at least one discharge hole (37) that connects the conduit (26) to the discharge channel (36).

7. The device according to any one of claims 1 to 6, wherein, The conduit (26) includes a plurality of top portions and a plurality of bottom portions, the top portions and the bottom portions following each other in an alternating manner.

8. The apparatus according to claim 7 when dependent on one of claims 3 to 6, wherein, The discharge channel (36) is connected to at least one of the bottom portions.

9. The device according to claim 8, wherein, The discharge channel (36) is connected to all of the bottom portions.

10. The device according to claim 2 or one of claims 3 to 9 when dependent on claim 2, wherein, Each of the portions (27) of the conduit (26) has a flat shape.

11. The device according to claim 2 or one of claims 3 to 10 when dependent on claim 2, wherein, Each of said parts (27) is defined by a first inner surface (32) parallel to said radial inner surface (19) of said annular container (16), a second inner surface (33) facing and parallel to said first inner surface (32), and an edge inner surface (34) connecting said first inner surface (32) and said second inner surface (33); wherein said first inner surface (32) is farther from said radial inner surface (19) of said annular container (16) than said second inner surface (33).

12. The apparatus according to claim 11, wherein, The ratio of the area (A1) of said first inner surface (32) to the gap (g) between said first inner surface (32) and said second inner surface (33) is between 1000 mm and 2000 mm.

13. The device according to claim 11 or 12, wherein The ratio of the area (A1) of said first inner surface (32) to the width (C) of said vulcanization and molding cavity (11) is between 80 mm and 100 mm.

14. The device according to any one of claims 11 to 13, wherein, The ratio of the area (A1) of said first inner surface (32) to the first distance (d1) from said first inner surface (32) to said radial inner surface (19) of said annular container (16) is between 1000 mm and 2000 mm; said first distance (d1) is measured perpendicular to said first inner surface (32).

15. The device according to any one of claims 11 to 14, wherein, The ratio of the area (A1) of said first inner surface (32) to the minimum radial distance (d2) from said second inner surface (33) to said radial outer surface (20) of said annular container (16) is between 100 mm and 200 mm.

16. The device according to any one of claims 11 to 15, wherein, The ratio of the maximum inner diameter (D) of said vulcanization and molding cavity (11) to the minimum radial distance (d2) from said second inner surface (33) to said radial outer surface (20) of said annular container (16) is between 10 mm and 20 mm.

17. The device according to any one of claims 11 to 16, wherein, The ratio of the height (h) of said first inner surface (32) to the width (C) of said vulcanization and molding cavity (11) is between 0.7 and 0.9; said height (h) is measured in a diameter section of said annular container (16) and parallel to said first inner surface (32).

18. The device according to any one of claims 11 to 17, wherein, The ratio of the width (w) of said first inner surface (32) to the width (C) of said vulcanization and molding cavity (11) is between 0.4 and 0.6; said width (w) is measured along the circumferential direction of said annular container (16).

19. The apparatus according to any one of claims 11 to 18 when claim 11 depends on one of claims 7 to 9, wherein, When viewed in the radial direction, each of said parts (27) is a U-shaped section of said conduit (26); wherein the lower bend of said U-shaped section is one of the bottom parts of said conduit (26), and each of the two upper ends of said U-shaped section is connected to an adjacent U-shaped section through one of the top parts.

20. The device according to claim 2 or one of claims 3 to 19 when dependent on claim 2, wherein, Each of said parts (27) of said conduit (26) is defined by a groove formed in said radial inner surface (19) of said annular container (16) and a plate (28) closing said groove; wherein in said lowered position, said plate (28) engages with the radially outer part (22) of said circumferential sector (10).

21. The apparatus according to claim 20, wherein, The plate (28) is made of a material having a thermal conductivity between 100 W / (m*K) and 180 W / (m*K) and a hardness between 40 HB and 210 HB.

22. The device according to claim 2 or one of claims 3 to 21 when dependent on claim 2, wherein, When the annular container (16) is in the lowered position, each circumferential sector (10) is coupled to a plurality of the portions (27).

23. The device according to one of claims 1 to 22, wherein, The conduit (26) has an inlet (30) and an outlet (31), and the inlet (30) and the outlet (31) are formed on the radially outer face (20) of the annular container (16) and are close to each other.

24. The apparatus according to any one of claims 1 to 23, wherein, Each of the circumferential sectors (10) includes a support block (12) and a working section (13). The support block (12) includes the radially outer portion (22), and the working section (13) is mounted on the support block (12) and includes a working surface (14) configured to engage the tire (2) placed in the vulcanization and molding cavity (11).

25. A method for preheating circumferential sectors in an apparatus for vulcanizing and molding a tire, the method comprising: Providing an annular container (16) that is placed to surround a plurality of circumferential sectors (10) arranged around a central axis (Y-Y) or configured to be placed to surround a plurality of circumferential sectors arranged around a central axis, the plurality of circumferential sectors (10) defining a vulcanization and molding cavity (11); Causing a heating medium to flow through a waveform pattern formed in the annular container (16), the waveform pattern extending from the top (17) to the bottom (18) of the annular container (16) and from the bottom (18) to the top (17); Wherein the radially inner face (19) of the annular container (16) contacts or is configured to be placed in contact with the radially outer portion (22) of the circumferential sector (10).

26. The method according to claim 25, the method comprising: Causing the heating medium to flow closer to the radially inner face (19) of the annular container (16) than to the radially outer face (20) of the annular container (16).

27. The method according to claim 25 or 26, wherein The average velocity of the heating medium in the waveform pattern is between 15 m / s and 25 m / s.

28. The method according to any one of claims 25 to 27, wherein, The flow rate of the heating medium passing through the waveform pattern portion is between 4 m 3 / s and 8 m 3 / s.

29. The method according to any one of claims 25 to 28, wherein, The heating medium is steam, and the method further comprises: discharging a condensed portion of the steam from the waveform pattern.

30. The method according to claim 29, wherein, Performing the discharging while the steam is flowing through the waveform pattern.

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