Tire building process

Abstract

A forming process is disclosed, wherein a green tyre for forming is formed in a tyre mould (1), preferably in a tyre mould without venting holes. The tyre mould (1) has one or more movable elements for moving the tyre mould (1) from an open position to a closed position. The tyre mould (1) comprises an actuating ring (31), a top plate (25), a bottom plate (23), upper and lower side members (7, 9), a plurality of mould segments (19), which upper and lower side members (7, 9) and plurality of mould segments (19) define a mould cavity, and further comprises sealing means for sealing the mould cavity, which sealing means comprises one or more closing sealing members (39, 41, 43, 45, 47). The process comprises providing said tyre mould (1); placing a green tyre in the mould cavity; placing one or more closing sealing members (39, 41, 43, 45, 47) in the vicinity of the mating surface, wherein by bringing the tyre mould (1) to a partially closed position, the one or more closing sealing members (39, 41, 43, 45, 47) face the mating surface without being in contact with the mating surface; and drawing a vacuum on the mould cavity, thereby causing the one or more closing sealing members (39, 41, 43, 45, 47) to move or deform by suction forces until they come into contact with the mating surface, thereby causing the mould cavity to be sealed in a gas-tight manner.

Description

TECHNICAL FIELD

[0001] The present invention relates to a forming process for producing pneumatic and non-pneumatic tires, in particular tires having a visual appearance. It also relates to a tire mold having a vacuum device for evacuating a mold cavity suitable for implementing the forming process. BACKGROUND

[0002] It is known to place an uncured tire, also called "green tire", into a tire mold, to provide it with a specific tread design on its radially outer surface and to cure it. After the tire mold is closed, the tire is cured at high temperature, wherein gas or air between the tire mold and the tire can be evacuated through small venting passages / channels in the tire mold. Due to this process of including such venting passages in the tire mold, so-called burrs can remain and protrude from the tire surface. Avoiding the presence of such burrs is beneficial to improve the appearance of the tire.

[0003] Different venting techniques are known which rely on complex small venting devices to avoid or make burrs smaller. However, each mold segment has to be provided with several hundred of such venting devices or channels. Especially in the case of winter tires, because of the tread blocks and their fine sipes, all the tiny elements of the tread have to be provided with a corresponding venting passage in the mold segments. Ensuring venting in this way is both expensive and time consuming. The venting devices can also clog, which can lead to quality problems and requires intensive cleaning or maintenance.

[0004] Another known technique is to evacuate the tire mold before curing the tire, the idea being to remove air before curing, thus minimizing the amount of venting, which helps to significantly reduce costs and improve the appearance of the tire. For example, EP-A-2 881 230 describes such a tire mold and process. This document describes a system for providing a vacuum in a segmented tire mold, the system comprising a vacuum vessel and a segmented tire mold. The vacuum vessel seals the tire mold, making it airtight. The tire mold has an upper sidewall assembly and a lower sidewall assembly, a plurality of radially movable tread mold segments operable with the upper and lower sidewall assemblies to define a tire mold cavity in a closed position of the tire mold, a tapered actuating ring assembly surrounding the tread mold segments for providing radial movement of the tread mold segments in engagement with the upper and lower sidewall assemblies. The vacuum vessel comprises a top sealing means between the actuating ring assembly and the upper sidewall assembly, and a bottom sealing means between the actuating ring assembly and the lower sidewall assembly, so that the tire mold is airtight and ready to be evacuated or evacuated only when fully closed. The top and bottom sealing means comprise silicone. The tire mold and the vacuum vessel do not have a sliding seal.

[0005] US Patent 4,573,894 and US Patent 4,595,553 both describe a method and apparatus in which a tire mold is closed to within about one inch of full closure, a green tire is placed in the tire mold for forming, and then, prior to full closure of the mold, the tire mold is evacuated using a vacuum conduit to evacuate the air in the mold cavity, eliminating the need for vent holes in the tire mold. The tire mold can be free of vent holes in the tread, sidewall and bead portions of the tire mold and include at least one vacuum conduit along the parting line so that the mold cavity can be evacuated to no more than 16,932 Pa using a vacuum source in no more than 60 seconds. A seal is disposed radially outside the vacuum conduit along the parting line and, if necessary, adjacent to any movable beads associated with the tire mold. The seal is preferably a type in which a pressure differential experienced by one sealing surface and an opposing sealing surface results in a more effective sealing arrangement.

[0006] A similar idea is found in US Patent 7,056,109 which describes a tire vulcanization apparatus comprising an upper plate and a lower plate which can be displaced relatively towards or away from each other and a tire mold for vulcanizing and forming a tire arranged between the upper plate and the lower plate. The tire mold comprises upper and lower side mold members arranged on the upper plate side and the lower plate side, respectively, and a plurality of sector-shaped mold members arranged between the upper and lower side mold members. An outer ring for positioning the sector-shaped mold members in a radial direction is arranged on the lower plate side. Actuator means for opening the sector-shaped mold members are arranged on the lower plate which can be raised vertically.

[0007] CN-A-109176988 discloses a sealing device cooperating with a guide ring and a base of an evacuated tire mold to seal the evacuated tire mold. The sealing device comprises a first seal, a floating seal ring and an elastic device. The base has a first annular groove arranged circumferentially, and the floating seal ring is arranged in the first annular groove by the elastic device. The elastic device is configured to provide an elastic force to make the floating seal ring close to the guide ring. The first seal is arranged at an end of the floating seal ring close to the guide ring, and the first seal is configured to make the guide ring and the sealing device cooperate to achieve sealing.

[0008] CN-A-209504658 describes a vacuum sealing device comprising an adjusting member, an elastic device and a first seal. The base is provided with an annular groove formed in the circumferential direction, and the adjusting member is arranged in the annular groove by the elastic device. The elastic device is configured to provide an elastic force to make the adjusting member close to the intermediate mold sleeve. The first seal is embedded in an end of the adjusting member close to the intermediate mold sleeve; the first seal is configured to achieve sealing between the intermediate mold sleeve and the base. The vacuum sealing device further comprises a second seal. The second seal is arranged between the adjusting member and the annular groove side wall.

[0009] While the above documents describe interesting constructions, there is still a need for further development, for example, to improve the durability of at least part of the seal, and / or to effectively evacuate air / gas from the mould to obtain a smooth visual appearance of the tyre surface. SUMMARY

[0010] The present invention relates to a process according to claim 1.

[0011] The dependent claims relate to preferred embodiments of the invention.

[0012] The building process according to the present invention can meet one or more of the above needs, wherein a vacuum is created within the mould cavity before the tyre mould is fully closed, and preferably before a cutting element such as a blade contacts the green tyre surface, and wherein the sealing by the closing sealing member is not achieved by compression of said closing sealing member, but by contact between the closing sealing member and the mating surface. The building process and the tyre mould of the present disclosure are remarkable in that this contact is achieved by movement and / or deformation of the closing sealing member(s) by suction force generated by the Venturi effect. In the tyre mould and building process according to the present disclosure, the vacuum means are activated before the sealing of the tyre mould, as the air flow generated by the activation of the vacuum means will induce the movement and / or deformation of the closing sealing member(s) from a rest state to their working state of sealing the tyre mould.

[0013] According to a preferred aspect of the invention, a building process is provided, wherein a green tyre is formed and then built in a tyre mould. The tyre mould has one or more movable elements displaceable to bring or cause the tyre mould into an open or closed position. The tyre mould preferably comprises one or more of an actuation ring, a top plate, a bottom plate, upper and lower side members, a plurality of mould segments and slides, and optionally vacuum means. Furthermore, the upper and lower side members and the plurality of mould segments define a mould cavity, and the tyre mould further comprises sealing means for sealing the mould cavity, comprising one or more closing sealing members, wherein the process comprises the following steps:

[0014] - providing a tyre mould having one or more closing sealing members;

[0015] - placing a green tyre in the mould cavity;

[0016] - placing the one or more closing sealing members in proximity of the mating surface so as to face the mating surface without contacting the mating surface by bringing the tyre mould to a partially closed position;

[0017] - drawing a vacuum on (or in other words in) the mould cavity, causing the one or more closing sealing members to move or deform by suction force until they are in contact with the mating surface, thereby sealing the mould cavity in a gas-tight manner.

[0018] According to another preferred aspect of the present application, a building process is provided, wherein a green tyre having a tread, a sidewall and a bead portion is formed and then built in a tyre mould. The tyre mould has one or more movable elements displaceable to bring or cause the tyre mould into an open or closed position. The tyre mould preferably comprises an actuation ring, a top plate, a bottom plate, upper and lower side members, a plurality of mould segments and slides and optionally a vacuum device. Furthermore, the upper and lower side members and the plurality of mould segments define a mould cavity and the tyre mould further comprises sealing means for sealing the mould cavity comprising one or more closing sealing members, wherein the process comprises the following steps:

[0019] - providing a tyre mould having one or more closing sealing members placed on one or more carrier elements, wherein each of the one or more closing sealing members is associated with a mating face and one closing sealing member is movable relative to the other during the travel of the one or more movable elements between an open position and a closed position of the tyre mould;

[0020] - opening the tyre mould and placing the green tyre into the mould cavity;

[0021] - placing the one or more closing sealing members in the vicinity of the mating face (or in other words, moving the one or more closing sealing members to a position close to and / or spaced apart from the mating face) so as to face the mating face without contacting the mating face by bringing the tyre mould to a partially closed position, wherein the one or more closing sealing members are in a rest state and spaced apart from the mating face by a distance of at most 1.5 mm;

[0022] - drawing a vacuum on the mould cavity, thereby causing the one or more closing sealing members to change from their rest state to a working state in which they are in contact with the mating face they are associated with.

[0023] According to another preferred aspect of the present application, a building process is provided, wherein a green tyre having a tread, a sidewall and a bead portion is formed and then built in a tyre mould. The tyre mould has one or more movable elements displaceable to bring or cause the tyre mould into an open or closed position, wherein the tyre mould optionally comprises one or more of an actuation ring, a top plate, a bottom plate, upper and lower side members, a plurality of mould segments and slides and a vacuum device. The upper and lower side members and the plurality of mould segments define a mould cavity and the tyre mould further comprises sealing means for sealing the mould cavity comprising one or more closing sealing members. The mould segments exhibit an inner building surface having one or more cutting elements, wherein the process comprises the following steps:

[0024] - providing a tire mold having one or more closing sealing members placed on one or more carrier elements; each of the one or more closing sealing members is associated with a mating face, and one closing sealing member is movable with respect to the other during displacement of the one or more movable elements from an open position to a closed position of the tire mold;

[0025] - opening the tire mold and placing the green tire into the mold cavity;

[0026] - placing the one or more closing sealing members in the vicinity of the mating faces so as to face the mating faces without contacting the mating faces by bringing the tire mold to a partially closed position, wherein the one or more closing sealing members are in a rest state and are spaced apart from the mating faces by a distance of at most 1.5 mm, and wherein the one or more cutting elements are not in contact with the green tire;

[0027] - drawing a vacuum on the mold cavity, causing the one or more closing sealing members to pass from their rest state to a working state in which they are in contact with the mating faces with which they are associated, thereby sealing the mold cavity;

[0028] - further wherein, as soon as the tire mold reaches its partially closed position before closing the tire mold, the step of drawing a vacuum on the mold cavity is initiated.

[0029] In a preferred aspect of the invention, the molding process uses a tire mold, preferably a tire mold without venting, or in other words, having mold segments without venting passages and / or venting devices.

[0030] In a preferred aspect of the invention, the method further comprises the step of closing the tire mold while the vacuum means are activated (or active), or in other words, while a vacuum is drawn, and the step of curing the tire, wherein during the curing step the vacuum means are deactivated, or in other words, the vacuum is stopped, causing the one or more closing sealing members to pass from their working state back to their rest state.

[0031] It will be appreciated that the one or more closing sealing members can pass from their rest state, in which they are not in contact with the associated mating face, to their working state, in which each closing sealing member is in contact with and / or pressed against the associated mating face. In fact, before the tire mold is sealed, activation of the vacuum means is initiated to draw a vacuum in the mold cavity (or to draw a vacuum within the mold cavity). This causes an air flow to pass between the one or more closing sealing members and the mating faces with which they are associated. The suction force resulting from the Venturi effect causes the one or more closing sealing members to move and / or deform, causing them to pass from their rest state to their working state, thereby sealing the mold cavity, i.e. the tire mold cavity, in a gas-tight manner.

[0032] The suction caused by the Venturi effect is possible because the one or more closing sealing members are placed next to the mating face when the mold is still open, i.e. in the partially closed position of the tire mold. In other words, the one or more closing sealing members are close enough to the one or more associated mating faces to create a constriction, thus promoting an increase in the air flow velocity next to the one or more closing sealing members when the vacuum device is activated. The one or more closing sealing members can pass from their rest state to their working state by deformation, displacement or both deformation and displacement. The displacement of the one or more closing sealing members caused by the suction is not a displacement of their carrier element, but a displacement that occurs with respect to their carrier element.

[0033] For example, the step of drawing a vacuum on the mold cavity comprises the one or more closing sealing members passing from their rest state, in which they are spaced apart from the mating face, to their working state, in which they contact said mating face in a sealing manner, wherein the one or more closing sealing members pass from their rest state to their working state by deformation, displacement or both deformation and displacement.

[0034] For example, each of the one or more closing sealing members is associated with one mating face, and during the displacement of the one or more movable elements, one closing sealing member is movable with respect to the other.

[0035] In a preferred aspect of the present disclosure, the one or more closing sealing members are made of an elastic and / or elastomer-based material. Preferably, the elastic material comprises an elastomer selected from the group consisting of resin-cured butyl rubber, silicone rubber, phenolic-cured butyl rubber and fluorocarbon rubber, and any mixture thereof.

[0036] Since the one or more closing sealing members are in their working state only when the vacuum device is activated, this means that they are in their rest state when the vacuum device is deactivated, such as during tire curing. Minimizing the time during which the one or more closing sealing members are in their working state improves their durability.

[0037] The partially closed position of the tire mold is a position in which the one or more closing sealing members are placed next to the mating face so as to face the mating face without contacting it when the tire mold is partially open and can seal the tire mold by the Venturi effect.

[0038] According to a preferred embodiment of the present disclosure, the vacuum device is activated during the closing of the tire mold when the tire mold is in its partially closed position. For example, the vacuum device can be provided remotely and can be part of the tire mold or can not be. In particular, the vacuum device does not necessarily have to be part of the tire mold.

[0039] For example, the vacuum device is activated to draw a vacuum on the tire mold in a time range of 5 to 40 seconds, preferably 7 to 30 seconds, more preferably 9 to 20 seconds.

[0040] For example, in the partially closed position of the tire mold or in the closed position of the tire mold, the one or more closing sealing members are spaced apart from the mating surface by a distance of at most 2.0 mm, preferably at most 1.8 mm, more preferably at most 1.5 mm, even more preferably at most 1.2 mm, most preferably at most 1.0 mm or even most preferably at most 0.8 mm.

[0041] For example, in the partially closed position of the tire mold, the one or more closing sealing members are spaced apart from the mating surface by a distance in the range of 0.1 mm to 2.0 mm, preferably 0.1 mm to 1.8 mm, more preferably 0.2 mm to 1.5 mm, even more preferably 0.3 mm to 1.2 mm and most preferably 0.4 mm to 1.0 mm or 0.5 mm to 0.8 mm.

[0042] For example, the one or more movable elements can be displaced from an initial position to a final position to bring the tire mold into the open or closed position and in the partially closed position of the tire mold, the one or more movable elements are in an intermediate position and still have a stroke to reach their final position to close the tire mold.

[0043] For example, in the partially closed position of the tire mold, the one or more movable elements still have a stroke of at least 3.0 mm, preferably at least 5.0 mm, more preferably at least 6.0 mm, even more preferably at least 8.0 mm and most preferably at least 10.0 mm before the tire mold reaches its closed position.

[0044] For example, in the partially closed position of the tire mold, the one or more movable elements still have a stroke of 3.0 mm to 25.0 mm, preferably 5.0 mm to 20.0 mm, more preferably 6.0 mm to 18.0 mm, even more preferably 8.0 mm to 15.0 mm before the tire mold is closed.

[0045] For example, the mold segment has an inner shaping surface with one or more cutting elements, which are spaced apart from the green tire when the tire mold is in its open position and which contact the green tire to cut its tread portion when the tire mold is in its closed position. Furthermore, in the partially closed position of the tire mold, the one or more cutting elements are still spaced apart from the green tire so as to start the step of drawing a vacuum on the mold cavity before the one or more cutting elements contact the green tire.

[0046] For example, the mold segment has an inner forming surface with one or more cutting elements having a given height, and in the partially closed position of the tire mold, the one or more movable elements still have a stroke greater than the height of the one or more cutting elements, before the tire mold is closed.

[0047] For example, the mold segment has an inner forming surface with one or more cutting elements having a given height, and in the partially closed position of the tire mold, the one or more cutting elements are still spaced apart from the green tire.

[0048] For example, the mold segment has an inner forming surface with one or more cutting elements, and, in the partially closed position of the tire mold, the cutting elements are not in contact with the green tire, and the one or more closure sealing members are placed at a distance of at most 2.0 mm, preferably at most 1.8 mm, more preferably at most 1.5 mm, even more preferably at most 1.2 mm, most preferably at most 1.0 mm or at most 0.8 mm from the mating surface, so as to be movable and / or deformable by suction when the vacuum means are activated.

[0049] For example, the mold segment shows an inner forming surface with one or more cutting elements, and in the partially closed position of the tire mold, the one or more closure sealing members are placed at a distance of at most 2.0 mm, preferably at most 1.5 mm from the mating surface, so as to be movable and / or deformable by suction when the vacuum means are activated, and before the tire mold is closed, the one or more movable elements still have a stroke of at least 3.0 mm, preferably at least 5.0 mm, more preferably at least 6.0 mm, even more preferably at least 8.0 mm and most preferably at least 10.0 mm.

[0050] In a preferred aspect of the application, the actuation ring, if present, is one of the one or more movable elements, which can be displaced to bring the tire mold into the open or closed position. For example, the actuation ring is one of the one or more movable elements and can be displaced from an initial position to a final position to close the tire mold, and the step of drawing a vacuum on the mold cavity is initiated before the actuation ring reaches its final position.

[0051] In a preferred aspect of the application, the one or more closure sealing members comprise an upper closure sealing member, a lower closure sealing member, or both.

[0052] For example, the one or more closure sealing members are O-ring sealing members. Preferably, the one or more closure sealing members comprise at least one O-ring sealing member made of an elastic material, having a defined diameter in its resting state, and wherein the step of drawing a vacuum on the mold cavity comprises increasing the diameter of the at least one O-ring sealing member until it comes into contact with its associated mating surface.

[0053] Preferably, the O-ring sealing member has a circular or elliptical cross-section. For example, the one or more closing sealing members are T-shaped sealing members. Preferably, the one or more closing sealing members comprise at least one T-shaped sealing member made of an elastic material extending from a surface (in its resting state in a defined direction), wherein the step of drawing a vacuum on the mold cavity comprises tilting the at least one T-shaped sealing member until it contacts its associated mating face.

[0054] For example, the one or more carrier elements are one or more selected from a top plate, a bottom plate, and an actuating ring. The one or more carrier elements hold the one or more closing sealing members.

[0055] For example, the one or more closing sealing members are O-ring sealing members. For example, the one or more closing sealing members comprise an upper closing sealing member which is an O-ring sealing member placed on the top plate, and a lower sealing member which is a T-shaped sealing member held and / or anchored to the bottom plate or the actuating ring.

[0056] For example, the one or more closing sealing members are T-shaped sealing members. For example, the one or more closing sealing members comprise an upper closing sealing member which is a T-shaped sealing member held and / or anchored to the top plate, and a lower sealing member which is a T-shaped sealing member held and / or placed on the actuating ring.

[0057] A T-shaped sealing member is preferably considered as a seal having essentially a T-shaped cross-section. Preferably, the T-shaped seal has at least three (or has three) legs, wherein two of these legs are fixed and / or anchored to a carrier element, e.g. within a (complementary shaped) groove and / or aperture of the carrier element. The third leg extends from and / or is laterally tiltable relative to the direction of extension of the carrier element, such as by a suction force generated by a vacuum, e.g. using a vacuum device. This can be caused by a Venturi effect, for example.

[0058] For example, the one or more closing sealing members comprise an upper closing sealing member placed on the top plate, and the associated mating face is a vertical edge of the actuating ring or a vertical edge of an upper sealing plate fixed to the actuating ring.

[0059] Preferably, the vertical edge of the actuating ring or the vertical edge of the upper sealing plate has a flanged end extending essentially in a vertical direction downwards and defining the mating face. For example, the flanged end has a height in the range of at least 5 to 25 mm, preferably 7 to 20 mm or 10 to 15 mm.

[0060] In one embodiment, the upper closure sealing member is an O-ring sealing member and is arranged in a groove of the vertical wall of the top plate or in a recess of the vertical wall of the top plate and is held in place by a hook.

[0061] In another embodiment, the upper closure sealing member is a T-shaped sealing member which is anchored in a groove of the upper surface of the top plate and extends vertically such that the mating face faces the vertical side of the T-shaped sealing member.

[0062] In one embodiment, the one or more closure sealing members comprise a lower sealing member placed on the actuating ring, wherein the lower closure sealing member is an O-ring sealing member and is arranged in a groove of the vertical wall of the actuating ring.

[0063] For example, the one or more closure sealing members comprise a lower sealing member placed on the actuating ring, wherein the lower closure sealing member is an O-ring sealing member and is arranged in a groove of the vertical wall of the actuating ring, and the mating face is a vertically extending ledge arranged at the outer end of the bottom plate.

[0064] In a preferred aspect of the invention, the one or more closure sealing members comprise a lower sealing member which is a T-shaped sealing member and is anchored to the bottom plate or the actuating ring and extends vertically such that the mating face faces the vertical side of the T-shaped sealing member, the mating face being on the actuating ring or the bottom plate, respectively.

[0065] The present invention provides the following technical solutions.

[0066] 1. A forming process, wherein a green tyre is formed in a tyre mould (1), preferably in a tyre mould without vent holes, the tyre mould (1) having one or more movable elements to move the tyre mould (1) from an open position to a closed position, the tyre mould comprising an actuating ring (31), a top plate (25), a bottom plate (23), an upper side member and a lower side member (7, 9), a plurality of mould segments (19) and a slide (27), the upper side member and the lower side member (7, 9) and the plurality of mould segments (19) defining a mould cavity, and the tyre mould (1) further comprising sealing means for sealing the mould cavity, the sealing means comprising one or more closure sealing members (39, 41, 43, 45, 47); the process comprising:

[0067] providing the tyre mould (1);

[0068] placing a green tyre in the mould cavity;

[0069] characterized in that the process further comprises

[0070] placing said one or more closing sealing members (39, 41, 43, 45, 47) in the proximity of a mating surface, wherein, by bringing said tyre mould (1) to a partially closed position, said one or more closing sealing members (39, 41, 43, 45, 47) face said mating surface without being in contact with said mating surface;

[0071] drawing a vacuum on said mould cavity, causing said one or more closing sealing members (39, 41, 43, 45, 47) to move or deform by suction until they come into contact with said mating surface, thus causing said mould cavity to be sealed in airtight manner.

[0072] 2. The forming process according to solution 1, characterized in that each of said one or more closing sealing members (39, 41, 43, 45, 47) is associated with a mating surface and is movable with respect to the other during displacement of said one or more movable elements.

[0073] 3. The forming process according to solution 1 or 2, characterized in that, in said partially closed position of said tyre mould (1), said one or more closing sealing members (39, 41, 43, 45, 47) are spaced apart from said mating surface by a distance of at most 1.5 mm or in a range comprised between 0.2 mm and 1.5 mm or between 0.3 mm and 0.8 mm.

[0074] 4. The forming process according to at least one of the preceding solutions, characterized in that, in said partially closed position of said tyre mould, said one or more movable elements still have a stroke of at least 3.0 mm before said tyre mould reaches its closed position.

[0075] 5. The forming process according to at least one of the preceding solutions, characterized in that said step of drawing a vacuum on said mould cavity comprises a change from a rest condition, in which said one or more closing sealing members (39, 41, 43, 45, 47) are spaced apart from the mating surface, to a working condition, in which said one or more closing sealing members (39, 41, 43, 45, 47) are in contact with said mating surface, and in that said one or more closing sealing members (39, 41, 43, 45, 47) change from their rest condition to their working condition by one or more deformations and displacements.

[0076] 6. - Moulding process according to at least one of the preceding claims, characterized in that said mould segment (19) exhibits an inner shaping surface with one or more cutting elements; said one or more cutting elements being spaced apart from the green tyre when the tyre mould (1) is in its open position and being in contact with the green tyre to cut its tread portion when the tyre mould (1) is in its closed position, and wherein, in said partially closed position of the tyre mould (1), said one or more cutting elements are still spaced apart from the green tyre so as to start the step of drawing vacuum on the mould cavity before said one or more cutting elements come into contact with the green tyre.

[0077] 7. - Moulding process according to at least one of the preceding claims, characterized in that said actuation ring (31) is one of said one or more movable elements and is displaceable from an initial position to a final position to close the tyre mould (1), and wherein the step of drawing vacuum on the mould cavity is started before said actuation ring reaches its final position.

[0078] 8. - Moulding process according to at least one of the preceding claims, characterized in that said one or more closing sealing members (39, 41, 43, 45, 47) comprise an upper closing sealing member (47) placed on the top plate (25) and the associated counterface is a vertical edge of the actuation ring (31) or of an upper sealing plate (37) fixed to the actuation ring (31).

[0079] 9. - Moulding process according to at least one of the preceding claims, characterized in that said upper closing sealing member (47) is an O-ring sealing member and is arranged in a groove of a vertical wall of the top plate (25) or in a recess of a vertical wall of the top plate (25) and is preferably held in place by a hook (49).

[0080] 10. - Moulding process according to at least one of the preceding claims, characterized in that said upper closing sealing member is a T-shaped sealing member anchored in a groove of an upper surface of the top plate (25) and extending substantially vertically so that the counterface faces a substantially vertical side of the T-shaped sealing member.

[0081] 11. The forming process according to at least one of the preceding claims, characterized in that said one or more closure sealing members (39, 41, 43, 45, 47) comprise a lower sealing member (45) placed on said actuation ring (31), wherein said lower closure sealing member (45) is an O-ring sealing member and is arranged in a groove of a vertical wall of said actuation ring (31), and said mating face is a vertically extending ledge (29) arranged at an outer end of said bottom plate (23).

[0082] 12. The forming process according to at least one of the preceding claims, characterized in that said one or more closure sealing members (39, 41, 43, 45, 47) comprise a lower sealing member (41) which is a T-shaped sealing member and is anchored to said bottom plate (23) or to said actuation ring (31) and extends vertically so that said mating face faces a vertical side of said T-shaped sealing member, wherein said mating face is on said actuation ring (31) or on said bottom plate (23), respectively.

[0083] 13. The forming process according to at least one of the preceding claims, characterized in that each of said one or more closure sealing members (39, 41, 43, 45, 47) is associated with a mating face and is movable with respect to the other during the travel of said one or more movable elements between said open position and said closed position of said tire mold (1).

[0084] 14. The forming process according to at least one of the preceding claims, characterized in that said vacuum device is activated to draw a vacuum in said tire mold (1) for a time of from 5 to 40 seconds.

[0085] 15. The forming process according to at least one of the preceding claims, characterized in that it further comprises the step of closing said tire mold (1) and curing said tire while drawing a vacuum, wherein said vacuum device for drawing a vacuum is deactivated during the curing step, causing said one or more closure sealing members to change from their working state back to their rest state.

[0086] As used herein, the terms "comprises", "comprising", and "comprised of" are synonymous with "includes", "including", or "contains", "containing", and are inclusive or open-ended and do not exclude additional, non-recited members, elements, or method steps. The terms "comprises", "comprising", and "comprised of" also include the term "consists of".

[0087] "Slit" means a narrow groove of siped tread molded into a tread element.

[0088] "Green tire" means a tire in an uncured state, i.e. prior to the vulcanization step.

[0089] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one or more embodiments" in various places in the specification are not necessarily all referring to the same embodiment, and some embodiments can be widely BRIEF DESCRIPTION OF DRAWINGS

[0090] Figure 1 is a partial cross-sectional view of a tire mold according to one embodiment of the present application.

[0091] Figure 2 is a schematic view of an upper closure sealing member which is an O-ring that has not yet faced its mating surface.

[0092] Figure 3 is a schematic view of an upper closure sealing member which is an O-ring that seals the tire mold when the tire mold is still partially open.

[0093] Figure 4 is a schematic view of an upper closure sealing member which is an O-ring that seals the tire mold when the tire mold is closed and the vacuum means is still active so that the sealing member is in contact with the mating surface.

[0094] Figure 5 is a schematic view of an upper closure sealing member which is an O-ring that seals the tire mold when the tire mold is closed and the vacuum means is no longer active so that the sealing member returns to its rest state, i.e. spaced apart from the mating surface.

[0095] Figure 6 is a schematic view of an upper closure sealing member which is a T-shaped sealing member that has not yet faced its mating surface.

[0096] Figure 7 is a schematic view of an upper closure sealing member which is a T-shaped sealing member that seals the tire mold when the tire mold is still partially open.

[0097] Figure 8 is a schematic view of an upper closure sealing member which is a T-shaped sealing member that seals the tire mold when the tire mold is closed and the vacuum means is still active so that the sealing member is in contact with the mating surface.

[0098] Figure 9 is a schematic view of an upper closure sealing member, which is a T-shaped sealing member that seals the tire mold when the tire mold is closed and the vacuum means is no longer activated so that the sealing member returns to its rest state, i.e. spaced apart from the mating surface.

[0099] Figure 10 is another partial cross-sectional view of a tire mold according to an embodiment of the present application. DETAILED DESCRIPTION

[0100] According to embodiments of the present application, the one or more closure sealing members do not work in a compressed state, but rather perform their sealing function by deforming and / or displacing towards their associated mating surface until they come into (sealing) contact with their associated mating surface. Once the vacuum means is deactivated and the vacuum suction ceases, the one or more closure sealing members return to their rest state. Thus, the one or more closure sealing members are no longer in a deformed, displaced or compressed state, but rather in a rest state during curing of the tire. It is found that this can improve the lifetime of the one or more closure sealing members compared to closure sealing members that are in a deformed, displaced or compressed state during curing of the tire, i.e. at the highest temperatures.

[0101] In embodiments according to the present application, the molding process comprises the following steps:

[0102] - providing a tire mold having one or more closure sealing members;

[0103] - placing a green tire in the mold cavity;

[0104] - placing the one or more closure sealing members in proximity of the mating surface so as to face the mating surface without contacting the mating surface by bringing the tire mold to a partially closed position;

[0105] - drawing a vacuum on the mold cavity, causing the one or more closure sealing members to move or deform under the action of the suction until they come into contact with the mating surface, thereby sealing the mold cavity in a gas-tight manner.

[0106] Preferably, the green tire has a tread, a sidewall and a bead portion. In embodiments according to the present application, the tire mold has one or more movable elements that are displaceable to bring the tire mold into an open or closed position. The tire mold comprises an actuating ring, a top plate, a bottom plate, upper and lower side members, a plurality of mold segments and slides, and a vacuum means. The upper and lower side members and the plurality of mold segments define a mold cavity, and the tire mold further comprises sealing means for sealing the mold cavity, which comprises one or more closure sealing members.

[0107] In one embodiment, the process further comprises the steps of closing the tire mold when the vacuum device is activated and curing the tire, wherein the vacuum device is deactivated during the curing step, causing the one or more closing sealing members to return from their working state to their rest state.

[0108] For example, the mold segments have an inner shaping surface with one or more cutting elements that are spaced apart from the green tire when the tire mold is in its open position and that contact the green tire to cut its tread portion when the tire mold is in its closed position. Moreover, in the partially closed position of the tire mold, the one or more cutting elements are still spaced apart from the green tire so as to start the step of drawing a vacuum on the mold cavity before the one or more cutting elements contact the green tire. For example, the actuation ring can be moved from the open position to the closed position and the step of drawing a vacuum on the mold cavity is started before the actuation ring reaches its closed position.

[0109] The vacuum device can be activated to draw a vacuum on the tire mold for a time ranging from 3 to 60 seconds, preferably from 5 to 40 seconds, more preferably from 7 to 30 seconds, even more preferably from 9 to 20 seconds.

[0110] In another embodiment, the tire mold has one or more movable elements that can be displaced to bring the tire mold into an open or closed position, the tire mold comprising an actuation ring, a top plate and a bottom plate, upper and lower side members, a plurality of mold segments and a slider. The upper and lower side members and the plurality of mold segments define a mold cavity. The tire mold further comprises a vacuum device arranged to remove gas from the mold cavity when it is activated. Moreover, the tire mold has a sealing device comprising mating faces configured to cooperate with one or more closing sealing members to seal the mold cavity by contacting each other, wherein each of the one or more closing sealing members is associated with one mating face and one closing sealing member can move relative to the other during the movement of the one or more movable elements from the open position to the closed position of the tire mold. Moreover, when the vacuum device is not activated, the one or more closing sealing members are placed in a position where they face their associated mating face without contacting it both in the partially closed position of the tire mold and in the closed position of the tire mold.

[0111] One or more closure sealing members can change from their rest condition, in which they are not in contact with the mating surface, to their working condition, in which they are in contact with said mating surface, wherein the one or more closure sealing members can be moved and / or deformed by the suction force caused by the Venturi effect generated by the activation of the vacuum means. In working conditions, the mould cavity is sealed in a gas-tight manner. Thus, the tyre mould can be sealed before reaching the closed position and the gas evacuated from the mould cavity. Once the tyre mould is closed, there is no longer a need to seal the tyre mould in a gas-tight manner so that the one or more closure sealing members can return to their rest condition. In particular, while the tyres are curing, they do not contact their associated mating surface. The tyre mould is gas-tight (preferably a few millimetres) before the closed end position of the movable elements of the tyre mould to remove the air and to help provide a mould without any venting system in the tread building section. The result is directly visible on the cured tyre. In particular, the tread outer surface or appearance is improved (i.e. no burrs and / or venting marks on the tread surface). At the same time, the durability of the one or more closure sealing members is improved since they are subjected to stress for only a few seconds, i.e. when the vacuum means are active.

[0112] Reference is now made to Figure 1 which illustrates a first embodiment of a tyre mould 1. The tyre mould 1 comprises a plurality of mould segments arranged to form an annular ring when assembled. The outer tread surface of the tyre is formed by the inner building surface 3 of the mould segments corresponding to the outer surface tread building elements. The inner building surface has a plurality of fine slits and / or blades (not shown) for building the tread pattern in the green tyre 5. The mould segments are radially movable so as to allow the assembly and disassembly of the tyre mould around the green tyre 5.

[0113] The tyre mould 1 further comprises first and second sidewall plates 7, 9 for building the sidewalls of the tyre. Each sidewall plate 7, 9 connects the respective mould segments to form a smooth continuous surface from the tread to the sidewall. Each sidewall plate 7, 9 can comprise an optional radially outer lip 11 forming an L-shaped recess for receiving the first and second flanged ends of the mould segments therein. Each sidewall plate 7, 9 further comprises an optional radially inner extension or lip 13 forming a second L-shaped recess for receiving the mould bead rings (15, 17) therein. Each bead ring 15, 17 has a circular segment or curved portion for receiving a bead area of the green tyre thereon. The upper and lower sidewall plates 7, 9 cooperate with the plurality of tread segments and the top and bottom bead rings 15, 17 to define a mould cavity for building the green tyre 5.

[0114] The mould segments can comprise tread building elements 19 and support elements 21, or comprise tread building elements integral with the support elements, or comprise tread building elements integral with the support elements and integral with the shoes.

[0115] The mold segments can be formed from one or two elements. In Figure 1 In an embodiment, the mold segments are formed from two elements, a tread forming element 19 and a support element 21. However, in another embodiment, the tread forming element and the support element are integral and form a single element as the mold segment.

[0116] Regardless of how the mold segments are formed, the tire mold 1 is segmented and further includes a container housing.

[0117] The container housing generally includes a top plate and a bottom plate 23, 25. The bottom plate 23 has an inner annular body for supporting the sidewall plates 9 and the bead rings 17. A plurality of slides 27 surround the segments. The slides 27 have flanged ends therein for receiving and supporting the segments. The slides 27 have top and bottom faces for contacting the top and bottom plates 23, 25 and optionally a wear plate (not shown). The slides 27 are slidable in a radial direction. The container housing further includes an annular actuating ring 31. An inner radial surface 33 of the actuating ring 31 is angled so as to engage an angled outer surface 35 of the slides 27. In Figure 1 In the illustrated embodiment, the actuating ring 31 is one of the one or more movable elements that can be displaced to bring the tire mold into an open or closed position. However, one skilled in the art can adapt the present disclosure to tire mold configurations in which the actuating ring is not movable. Such configurations are also known to those skilled in the art and are described, for example, in U.S. Patent 7,056,109.

[0118] Now assuming that the actuating ring 31 is one of the one or more movable elements. As the actuating ring 31 is lowered from the open position to the closed position, the inner radial surface 33 of the actuating ring 31 engages the angled outer surface 35 of the slides 27, causing the slides to slide radially inward. The camming action of the actuating ring 31 moves the slides 27 radially inward. As the slides 27 move radially inward, the radially inner surfaces of the slides 27 engage the outer surfaces of the adjacent mold segments, causing the mold segments to move radially inward as the actuating ring 31 is lowered to the closed position defining a reduced diameter limit position, causing the blades and / or sipe cuts the surface of the green tire 5.

[0119] The tire mold 1 according to the present disclosure further includes an upper seal plate 37. The upper seal plate 37 is fixedly secured or connected to the actuating ring 31 via an upper seal member 39 so as to move therewith.

[0120] A bottom seal member 41 is placed between the contact face of the bottom plate 23 and the second sidewall plate 9. Similarly, a top seal member 43 is placed between the contact face of the top plate 25 and the first sidewall plate 7.

[0121] The tire mold of the present disclosure is remarkable in that it further comprises one or more closing sealing members 45, 47 arranged to seal the mold cavity before the tire mold 1 is closed upon activation of the vacuum means, for example before the actuation ring 31 reaches its closed position. The one or more closing sealing members 45, 47 can be chosen from one or more upper closing sealing members 47, one or more lower sealing members 45 or both. The one or more closing sealing members 45, 47 are different from other sealing members such as the upper sealing member 39, the bottom sealing member 41 and the top sealing member 43 in that they are associated with a mating surface wherein one closing sealing member is movable with respect to the other during displacement of the tire mold 1 from its open position to its closed position, i.e. during displacement of the movable elements of the tire mold 1, and in that the one or more closing sealing members 45, 47 can change from a position where they are not in contact with the mating surface to which they are associated to a position where they are in contact with the mating surface to which they are associated by suction force generated by activation of the vacuum means according to the Venturi effect, thereby sealing the mold cavity in airtight manner.

[0122] For example, the one or more closing sealing members 45, 47 are configured to change from their rest state to their working state by deformation, displacement or both.

[0123] For example, at least one of the one or more closing sealing members 45, 47 is of the O-ring type as illustrated in Figures 1 to 4 and Figure 10 Deformation and / or displacement of the at least one closing sealing member 45, 47 of the O-ring type means increasing its diameter until contact with the mating surface to which it is associated.

[0124] For example, at least one of the one or more closing sealing members 45, 47 is of the T-type as illustrated in Figures 6 to 10 Deformation and / or displacement of the at least one closing sealing member 45, 47 of the T-type means tilting of it (or of the leg of the T-type seal) until contact with the mating surface to which it is associated.

[0125] In a preferred embodiment, the one or more closing sealing members are made of an elastomeric material. Preferably, the elastomeric material comprises an elastomer selected from the group consisting of resin cured butyl rubber, silicone rubber, phenolic cured butyl rubber and fluorocarbon rubber and any mixture thereof.

[0126] In the embodiment illustrated in Figure 1 both the upper and lower closing sealing members 47, 45 are O-ring sealing members. However, the present disclosure encompasses embodiments wherein both the upper and lower closing sealing members are T-shaped sealing members and embodiments wherein the upper closing sealing member is an O-ring sealing member while the lower sealing member is a T-shaped sealing member (as illustrated inFigure 10 or wherein the upper closure sealing member is a T-seal member and the lower sealing member is an O-ring sealing member. The disclosure also encompasses embodiments wherein only one selected from the upper closure sealing member and the lower closure sealing member can change from a position or configuration in which it does not contact its mating surface to a position or configuration in which it does contact its mating surface via suction caused by the Venturi effect resulting from activation of the vacuum device.

[0127] For all embodiments, when one or more closure sealing members 45, 47 face their associated mating surface without contacting them, such as in a partially closed position of the tire mold or in a closed position of the tire mold, as long as the vacuum device is not activated, the members are optionally spaced from the respective mating surface by a distance D of at most 2.0 mm, preferably at most 1.8 mm, more preferably at most 1.5 mm, even more preferably at most 1.2 mm, most preferably at most 1.0 mm or at most 0.8 mm. The distance D is shown in Figure 2 , 5 , 6 and 9.

[0128] For example, when one or more closure sealing members 45, 47 face their associated mating surface without contacting them, such as in a partially closed position of the tire mold or in a closed position of the tire mold, as long as the vacuum device is not activated, the members are spaced from the respective mating surface by a distance D of 0.1 mm to 2.0 mm, preferably 0.1 mm to 1.8 mm, more preferably 0.2 mm to 1.5 mm, even more preferably 0.3 mm to 1.2 mm, most preferably 0.4 mm to 1.0 mm or 0.5 mm to 0.8 mm. The distance D is shown in Figure 2 , 5 , 6 and 9.

[0129] The one or more movable elements can be moved from an initial position to a final position, thereby bringing the tire mold into an open or closed position. A partially closed position of the tire mold is a first position during the travel of the moving elements, in which the one or more movable elements are in an intermediate position so that they have a travel to reach their final position to close the tire mold, but in which one or more closure sealing members are close enough to their associated mating surface so that they can be moved by suction caused by the Venturi effect upon activation of the vacuum device to seal the tire mold.

[0130] For example, in a partially closed position of the tire mold 1, the one or more movable elements still have a travel of at least 3.0 mm, preferably at least 5.0 mm, more preferably at least 6.0 mm, even more preferably at least 8.0 mm and most preferably at least 10.0 mm before closing the tire mold 1.

[0131] For example, in the partially closed position of the tire mold 1, the one or more movable elements still have a stroke of 3.0 mm to 25.0 mm, preferably 5.0 mm to 20.0 mm, more preferably 6.0 mm to 18.0 mm, even more preferably 8.0 mm to 15.0 mm, before the tire mold is closed.

[0132] For example, the mold segment has an inner forming surface with one or more cutting elements having a given height, and in the partially closed position of the tire mold 1, the one or more movable elements still have a stroke greater than the height of the one or more cutting elements before the tire mold is closed.

[0133] For example, the mold segment has an inner forming surface with one or more cutting elements. In the partially closed position of the tire mold, the one or more closure sealing members are spaced apart from the mating surface by a distance of at most 2.0 mm from their associated mating surface, so as to be movable and / or deformable by suction upon activation of the vacuum device at a moment when the cutting elements have not yet come into contact with the green tire. Preferably, said distance is at most 1.8 mm, more preferably at most 1.5 mm, even more preferably at most 1.2 mm, and most preferably at most 1.0 mm or at most 0.8 mm. For example, they are spaced apart by a distance ranging from 0.1 mm to 2.0 mm, preferably from 0.1 mm to 1.8 mm, more preferably from 0.2 mm to 1.5 mm, even more preferably from 0.3 mm to 1.2 mm, most preferably from 0.4 mm to 1.0 mm or from 0.5 mm to 0.8 mm.

[0134] For example, the mold segment has an inner forming surface with one or more cutting elements, wherein in the partially closed position of the tire mold, the one or more closure sealing elements are spaced apart from the mating surface by a distance of at most 2.0 mm, preferably at most 1.5 mm, so as to be movable and / or deformable by suction upon activation of the vacuum device at a moment when the one or more movable elements still have a stroke of at least 3.0 mm before the tire mold reaches its closed position. Preferably, said stroke is at least 5.0 mm, more preferably at least 6.0 mm, even more preferably at least 8.0 mm, and most preferably at least 10.0 mm.

[0135] In the illustrated embodiment, the upper closure sealing member 47 is placed on the top plate 25. The associated mating surface is the vertical edge of the upper sealing plate 37 fixed to the drive ring 31. In one embodiment not shown, the associated mating surface is the vertical edge of the actuation ring. This is the case, for example, when the upper sealing plate is integral with the actuation ring. Figures 1 to 5

[0136] ​As shown in the figure, the vertical edge of the actuating ring or the vertical edge of the upper sealing plate 37 has a flanged end 51 that extends vertically downward and defines a mating surface. For example, the height or length of the flanged end 51 ranges from at least 5 to 25 mm, preferably 7 to 20 mm or 10 to 15 mm.

[0137] like Figure 2 As shown, when the tire mold is opened, the upper closing sealing member 47 is not yet facing its associated mating surface 51. Figure 3 As shown, in the partially closed position of the tire mold, once the upper closing sealing member 47 faces its associated mating surface 51, the vacuum device is activated, thereby placing the upper closing sealing member 47 in its working position and sealing the tire mold. Figure 4 The illustration shows that because the vacuum device is still active, the upper closing sealing member 47 is in its working position, thus the tire mold is closed and sealed. Figure 5 The illustration shows that the closed tire mold is no longer sealed because the vacuum device is no longer activated, causing the upper closing sealing member 47 to return to its stationary position.

[0138] like Figure 4 and Figure 5 As shown, when the tire mold is closed, the top plate 25 may include a recess 53 for receiving the flanged end 51.

[0139] The upper closing sealing member 47 can be arranged in the groove 63 of the vertical wall of the top plate 25 (see...). Figure 4 and Figure 5 The hook 49 is located in a recess in the vertical wall of the top plate 25 and held in place by the hook 49. The hook 49 can be fixed to the top plate 25, such as... Figure 2 and 3 As shown, it can also be integrally formed with the top plate 25 as the wall of the groove 63, such as... Figure 4 and 5 As shown.

[0140] like Figures 2 to 5 As shown, the position of the upper closing sealing member 47 allows it to contact its mating surface, namely the flanged end 51 of the upper sealing plate 37. Therefore, the sealing member 47 provides a sealing function before the tire mold closes, i.e., when a stroke H remains between the upper sealing plate 37 and the upper surface 55 of the top plate 25. For example, the remaining stroke H before the tire mold closes is at least 3.0 mm.

[0141] like Figure 4 As shown, the outer surface of the flanged end 51 of the upper sealing plate 37 is the associated mating surface of the upper closing sealing member 47, and the flanged end 51 of the upper sealing plate 37 is one of the movable elements that are displaced to allow the tire mold to enter an open or closed position.Figure 3 and Figure 4 In the position Figure 5 In the position

[0142] Figure 1 It is shown that the tire mold 1 can comprise a lower closure sealing member 45 arranged between the bottom plate 23 and the actuating ring 31. For example, the lower closure sealing member 45 can be arranged in a groove of the vertical wall of the actuating ring 31 or in a recess of the vertical wall of the actuating ring 31 and held in place by a hook. The mating face of the lower closure sealing member 45 is the inner surface of the vertically extending ledge 29 arranged at the outer end of the bottom plate 23. The vertically extending ledge 29 preferably extends vertically upwards. For example, the vertically extending ledge 29 has a height in the range of 5 to 25 mm, preferably 7 to 20 mm or 10 to 15 mm. Here, the lower sealing member is placed on one of the movable elements, i.e. the actuating ring 31, which is displaced to bring the tire mold into the open or closed position, while its associated mating face is in a fixed position.

[0143] One or more closure sealing members are arranged in a position having the intended sealing function before the tire mold is fully closed, thereby allowing the suction to be started and the enclosed air and / or gas to be removed as soon as these sealing members have the sealing function (before the diameter reduction limit position is reached). Thus, the gas in the mold cavity can be removed by suction without the need to provide vent holes in the tread mold segments. The removal of the gas is preferably started before the blades, or in other words the cutting elements, contact the surface of the green tire. In a preferred embodiment, the tire mold is a vent hole free tire mold. In other words, the tread mold segments and / or the sidewall mold segments are free of vent holes and / or venting means.

[0144] Figures 6 to 10 The shown embodiment shows at least one closure sealing member 45, 47 which is a T-shaped sealing member.

[0145] As shown in the embodiment related to the upper closure sealing member 47 of Figures 6 to 9 As shown in the embodiment related to the upper closure sealing member 47 of Figure 6The tire mold is illustrated in an open position, wherein the mating face 59, here the vertical edge 59 of the upper sealing plate 37, has not yet faced the upper closure sealing member 47. The travel H of the closure sealing member, which can exert its sealing function before the tire mold is closed, corresponds to the height of the T-shaped sealing member from the upper surface of the top element. For example, the upper closure sealing member 47 is a T-shaped sealing member, which extends vertically upward from the upper surface 55 of the top plate 25 to the height of its outer vertical wall 57, which is at least 3.0 mm, preferably at least 5.0 mm, more preferably at least 6.0 mm, even more preferably at least 8.0 mm, and most preferably at least 10.0 mm. For example, the height of the T-shaped sealing member, determined from the upper surface 55 of the top plate 25, ranges from 5.0 to 25.0 mm, preferably from 7.0 to 20.0 mm, or from 10.0 to 15.0 mm. In this configuration, it is understood that the upper sealing plate 37 is one of the movable elements that are displaced to move the tire mold to the open or closed position.

[0146] The present disclosure also encompasses embodiments (not illustrated) wherein the height of the T-shaped sealing member, determined from the upper surface 55 of the top plate 25, ranges from 3.0 to 25.0 mm, and cooperates with a mating face that is a flanged end of an upper sealing plate or actuating ring. The present disclosure also encompasses embodiments (not illustrated) wherein the T-shaped sealing member is anchored on an upper sealing plate or actuating ring and extends vertically downward, and cooperates with a mating face of a vertical wall of the upper plate. Preferably, the height of the T-shaped sealing member ranges from 3.0 to 25.0 mm. Since in such embodiments the upper sealing member is anchored in an upper sealing plate, which is one of the movable elements that are displaced to move the tire mold to the open or closed position.

[0147] As Figure 7 illustrated in a partially closed position of the tire mold, once the upper closure sealing member 47 faces its associated mating face 59, the vacuum means are activated, thereby bringing the upper closure sealing member 47 in its working position, and the tire mold is sealed.

[0148] Figure 8 illustrated in a closed position of the tire mold, wherein the vacuum means are still in an activated state. Figure 9 illustrated in its closed position, wherein the vacuum means are no longer activated.

[0149] In one embodiment of the invention, after the mold is sealed, a green tire is pushed against the inner forming surface of the mold, which has one or more cutting elements, using a curing bladder. More specifically, the green tire is pressed outward against the mold surface by the internally fluid-expandable curing bladder. In this way, the green tire is shaped against an outer mold surface that defines the tire's tread pattern and sidewall construction. The tire is cured by applying heat. Typically, the bladder expands under internal pressure provided by a fluid, such as hot air, hot water, and / or steam, which also participates in the heat transfer for curing or vulcanization purposes. The tire can then be allowed to cool to a certain extent in the mold, sometimes aided by adding cold or cool water to the curing bladder. The mold is then opened, the bladder collapses by removing its internal fluid pressure, and the tire is removed from the tire mold.

[0150] The cured capsule used with the tire mold of the present invention is typically composed of butyl rubber. Butyl rubber is a copolymer consisting primarily of isobutylene and a small amount of diene monomers (typically isoprene) to provide sufficient unsaturation for cross-linking. Brominated copolymers of isobutylene and p-methylstyrene, readily available from ExxonMobil, are conveniently used in the manufacture of the cured capsule.

[0151] like Figure 7 and 8 As shown, the upper closing seal member 47 deforms due to tilting, so that the surface of its radially outer wall is pressed against the vertical edge 59 of the upper sealing plate 37. After the vacuum device (not shown) is deactivated, the upper closing seal member 47 returns to its stationary state so that it is spaced from its associated mating surface (here, the vertical edge 59 of the upper sealing plate 37) by a distance of 0.1 mm to 2.0 mm, preferably 0.1 mm to 1.8 mm, more preferably 0.2 mm to 1.5 mm, even more preferably 0.3 mm to 1.2 mm, and most preferably 0.4 mm to 1.0 mm or 0.5 mm to 0.8 mm. Therefore, the upper closing seal member 47 has a sealing function only under the suction of the vacuum device, thereby preventing contact between the upper closing seal member 47 and the upper sealing plate 37 before and after the vacuum device is operated, and thus avoiding extensive wear of the upper closing seal member 47.

[0152] exist Figure 10 In this embodiment, the lower closing sealing member 45 is anchored in the lower surface of the actuating ring 31 and extends vertically downward. The mating surface is the vertical edge 61 of the base plate 23. This configuration is noteworthy because the diameter of the base plate can be reduced.

[0153] The present disclosure should also encompass embodiments wherein the lower closure sealing member is fixed to the bottom of the radial outer wall of the actuation ring and wherein the associated mating face is the vertical edge of the bottom plate. The present disclosure also encompasses embodiments wherein the lower closure sealing member is fixed to the bottom plate and the associated mating face is the radial outer wall of the actuation ring.

Claims

1. A forming process wherein, A shaped green tyre is shaped in a tyre mould (1) having one or more movable elements to move the tyre mould (1) from an open position to a closed position, the tyre mould comprising an actuation ring (31), a top plate (25), a bottom plate (23), an upper and a lower side member (7, 9), a plurality of mould segments (19) and a slide (27), the upper and lower side member (7, 9) and the plurality of mould segments (19) defining a mould cavity, and the tyre mould (1) further comprising sealing means for sealing the mould cavity, the sealing means comprising one or more closing sealing members (39, 41, 43, 45, 47); the process comprising: providing the tyre mould (1); placing a green tyre in the mould cavity; characterized in that the process further comprises placing the one or more closing sealing members (39, 41, 43, 45, 47) in the vicinity of a mating face, wherein by bringing the tyre mould (1) to a partially closed position, the one or more closing sealing members (39, 41, 43, 45, 47) face the mating face without being in contact with the mating face; pulling a vacuum on the mould cavity, causing the one or more closing sealing members (39, 41, 43, 45, 47) to move or deform by suction forces until they are in contact with the mating face, thereby sealing the mould cavity in a gas-tight manner, the shaping process further comprising the steps of closing the tyre mould (1) and curing the tyre while vacuuming, wherein the vacuum means for vacuuming are deactivated during the curing step, causing the one or more closing sealing members to change from their working state back to their resting state.

2. The forming process of claim 1, wherein, Each of the one or more closing sealing members (39, 41, 43, 45, 47) is associated with a mating face and is movable relative to the other during displacement of the one or more movable elements.

3. A forming process according to claim 1 or 2, characterised in that, In the partially closed position of the tyre mould (1), the one or more closing sealing members (39, 41, 43, 45, 47) are spaced apart from the mating face by a distance of at most 1.5 mm.

4. A forming process according to claim 1 or 2, characterised in that In the partially closed position of the tyre mould, the one or more movable elements still have a stroke of at least 3.0 mm before the tyre mould reaches its closed position.

5. A forming process according to claim 1 or 2, characterised in that The step of pulling a vacuum on the mould cavity comprises the one or more closing sealing members (39, 41, 43, 45, 47) changing from their resting state, in which they are spaced apart from the mating face, to their working state, in which they are in contact with the mating face, and wherein the one or more closing sealing members (39, 41, 43, 45, 47) change from their resting state to their working state by one or more deformations and displacements.

6. A forming process according to claim 1 or 2, characterised in that The mold segment (19) exhibits an inner shaping surface with one or more cutting elements; the one or more cutting elements are spaced apart from the green tire when the tire mold (1) is in its open position and are in contact with the green tire to cut its tread portion when the tire mold (1) is in its closed position, and wherein, in the partially closed position of the tire mold (1), the one or more cutting elements are still spaced apart from the green tire so as to start the step of drawing a vacuum on the mold cavity before the one or more cutting elements come into contact with the green tire.

7. A forming process according to claim 1 or 2, characterised in that The actuating ring (31) is one of the one or more movable elements and is displaceable from an initial position to a final position to close the tire mold (1), and wherein the step of drawing a vacuum on the mold cavity is started before the actuating ring reaches its final position.

8. A forming process according to claim 1 or 2, characterised in that, The one or more closure sealing members (39, 41, 43, 45, 47) include an upper closure sealing member (47) placed on the top plate (25) and the associated mating face is a vertical edge of the actuating ring (31) or a vertical edge of an upper sealing plate (37) fixed to the actuating ring (31).

9. The forming process of claim 8, wherein, The upper closure sealing member (47) is an O-ring sealing member and is arranged in a groove of a vertical wall of the top plate (25) or in a recess of a vertical wall of the top plate (25).

10. The forming process of claim 8, wherein, The upper closure sealing member is a T-shaped sealing member anchored in a groove of an upper surface of the top plate (25) and extending substantially vertically with the mating face facing a substantially vertical side of the T-shaped sealing member.

11. A forming process according to claim 1 or 2, characterised in that The one or more closure sealing members (39, 41, 43, 45, 47) include a lower closure sealing member (45) placed on the actuating ring (31), wherein the lower closure sealing member (45) is an O-ring sealing member and is arranged in a groove of a vertical wall of the actuating ring (31) and the mating face is a vertically extending ledge (29) arranged at an outer end of the bottom plate (23).

12. A forming process according to claim 1 or 2, characterised in that The one or more closure sealing members (39, 41, 43, 45, 47) include a lower closure sealing member (41) which is a T-shaped sealing member and is anchored to the bottom plate (23) or to the actuating ring (31) and extends vertically so that the mating face faces a vertical side of the T-shaped sealing member, wherein the mating face is on the actuating ring (31) or on the bottom plate (23), respectively.

13. A forming process according to claim 1 or 2, characterised in that Each of the one or more closure sealing members (39, 41, 43, 45, 47) is associated with a mating face and is movable relative to the other during the travel of the one or more movable elements between the open position and the closed position of the tire mold (1).

14. A forming process according to claim 1 or 2, characterised in that, The vacuum device is activated to draw a vacuum in the tire mold (1) for a time of from 5 to 40 seconds.

15. A forming process according to claim 1 or 2, characterised in that, The shaped green tire is shaped in a tire mold without a vent hole.

16. The forming process of claim 9, wherein, The upper closure sealing member (47) is held in place by a hook (49).

17. A forming process according to claim 1 or 2, characterised in that, In the partially closed position of the tyre mould (1), the one or more closure sealing members (39, 41, 43, 45, 47) are spaced apart from the mating surface by a distance in the range 0.2 mm to 1.5 mm.

18. A forming process according to claim 1 or 2, characterised in that, In the partially closed position of the tyre mould (1), the one or more closure sealing members (39, 41, 43, 45, 47) are spaced apart from the mating surface by a distance in the range 0.3 mm to 0.8 mm.

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