Bonding of the tire base layer

Abstract

A method of providing a joint between a first tire base layer end portion and a second tire base layer end portion, the method comprising: providing a first length of a tire base layer having a first end portion, a first main portion, and a first pair of reinforcing elements; providing a second length of a tire base layer having a second end portion, a second main portion, and a second pair of reinforcing elements; and joining the first end portion and the second end portion to each other such that each reinforcing element of the first pair of reinforcing elements is aligned with a corresponding reinforcing element of the second pair of reinforcing elements.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for providing a joint between a first tire base layer end portion and a second tire base layer end portion. The present invention can further be extended to a method and apparatus for manufacturing a tire incorporating a method and apparatus for providing a joint between a first tire base layer end portion and a second tire base layer end portion.

Background Art

[0002] Tires (e.g., vehicle tires which may be any device for transporting people or goods) are typically manufactured using a batch process that requires manual labor during intervening steps of the process, as well as during some steps of the process itself. For example, bead wire is typically formed into a loop for use in a tire in an initial step, manually placed onto a loop of tire base layer material on a drum, and then the bead wire is fixed within the tire base layer. Next, a pre-formed rubber strip for forming a tread may be placed onto the tire base layer while on the drum. The combined loop of tread and tire base layer is moved to an expansion mold where curves are applied to the flat surface of the loop. The partially formed tire may then be manually placed into individual curing molds to further shape the tire and form a tread pattern during the curing process.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Such batch processes are inefficient in terms of time and cost. Therefore, it would be beneficial to enable a more efficient tire manufacturing process.

Means for Solving the Problems

[0004] Viewed from a first aspect, the present invention provides a method of providing a joint between a first tire base layer end portion and a second tire base layer end portion, the method comprising providing a first length of a tire base layer having a first end portion, a first main portion, and a first pair of reinforcing elements; providing a second length of a tire base layer having a second end portion, a second main portion, and a second pair of reinforcing elements; and joining the first end portion and the second end portion to each other such that each reinforcing element of the first pair of reinforcing elements is aligned with a corresponding reinforcing element of the second pair of reinforcing elements.

[0005] The tire base layer is a layer provided under the tread of the tire and providing a framework for the tire. In a pneumatic tire having an inner tube or inner liner, the base layer covers the inner tube or inner liner to provide protection, restrain the inner tube or inner liner, and thereby support resistance to internal pressure.

[0006] The tire base layer can include any suitable material for use in the base layer of a tire. For example, plastic or metal. Any such material may be provided in a mesh form including through-surface holes, or in a continuous / plate form, i.e., a continuous material, without through-surface holes.

[0007] The tire base layer may include a fiber composite material and may thus sometimes be referred to as a tire carcass.

[0008] A reinforcing element is any feature that provides a stiffening effect to the tire carcass. Thus, the reinforcing element helps to increase the rigidity of the tire carcass and its ability to maintain its shape and withstand the internal pressure, while the body of the tire carcass may be a flexible material that enhances the toughness of the carcass and helps the tire to grip the surface during use. The reinforcing element may be a modified portion of the tire carcass and thus may be integral with the carcass. The reinforcing element may be formed of a material different from that of the tire carcass and may be embedded in the tire carcass. For example, the reinforcing element may include a relatively rigid polymer such as polyamide having a high tensile strength, and the body of the tire carcass may include a relatively flexible polymer such as a fiber-reinforced thermoplastic elastomer.

[0009] Thus, the first pair of reinforcing elements and the second pair of reinforcing elements are aligned when the lengths of the tire carcass are joined. The reinforcing elements may overlap in the longitudinal and / or transverse directions of the joined tire carcass within the region of the joint.

[0010] The first pair of reinforcing elements may include a first pair of bead wires, and the second pair of reinforcing elements may include a second pair of bead wires.

[0011] The reinforcing element may be in the form of a bead wire. A bead wire is a length of material similar to a thread in that it extends substantially in one dimension. A bead wire is not necessarily limited to a metal wire. A bead wire may include metal, a thermoplastic polymer, or a thermosetting polymer. A bead wire may include a suitable aramid material.

[0012] The first length of tire carcass may be continuous with the second length of tire carcass such that the first end portion and the second end portion are opposite longitudinal ends of a single tire carcass.

[0013] A complete circular tire carcass may be formed from a single length of tire carcass such that one longitudinal end is joined to the other longitudinal end.

[0014] Alternatively, a plurality of tire plies may be joined at their respective longitudinal ends to form a loop.

[0015] The method may include joining the first end portion to the second end portion via a sleeve, a seam, welding, solder, and / or glue.

[0016] A sleeve of additional material may be disposed around the joint between the first end portion and the second end portion, may be tight enough to form the joint, and / or may include an adhesive. The sleeve may be applied over a joint that could have been formed by welding, soldering, and / or gluing.

[0017] Joining the first end portion to the second end portion may include forming a contact area between the first end portion and the second end portion of the tire ply and performing a welding operation to bond the first end portion and the second end portion within the contact area.

[0018] Thus, the end portion of the tire ply is fixed at the location where contact occurs between the two lengths of the tire ply.

[0019] The welding operation may include one or more of heat tool welding, hot gas welding, ultrasonic welding, spin welding, infrared welding, high frequency welding, vibration welding, induction welding, microwave welding, resistance welding, extrusion welding, and laser welding.

[0020] The welding operation may include raising the temperature of the contact area between the first end portion and the second end portion and applying pressure for a length of time sufficient to properly bond the first end portion and the second end portion within the contact area.

[0021] The heat may be applied from an external heat source, and / or the heat may be generated by mechanical movement, and / or the heat may be generated using electricity magnetism.

[0022] The welding operation may include vibrating a contact area between a first end portion and a second end portion, and applying pressure for a length of time sufficient to properly bond the first end portion and the second end portion within the contact area. Thus, the welding operation may use friction welding techniques.

[0023] Joining the first length of tire carcass ply and the second length of tire carcass ply to each other may include forming a contact area between a first end portion and a second end portion of the tire carcass ply, and the method may include providing glue within the contact area and applying pressure to the contact area.

[0024] Thus, the end portions of the tire carcass ply are fixed at the location where contact occurs between the two lengths of tire carcass ply.

[0025] Forming a contact area between a first end portion and a second end portion of the tire carcass ply may include placing the first end portion over the second end portion.

[0026] Thus, the first end portion of the tire carcass ply overlaps the second end portion of the tire carcass ply. Thus, there is a thickness that is twice that of the tire carcass ply in the contact area in the thickness direction. Thus, when a tire is formed using the joined tire carcass ply, there is additional thickness in the radial direction of the tire within the contact area. The extra strength from the increased thickness helps to minimize the strength reduction caused by the joining. Welding and / or adhesion may be performed in the overlapping area.

[0027] In this case, the first pair and the second pair of reinforcing elements may be aligned such that the first pair overlaps the second pair in the thickness direction.

[0028] The contact area can be sized appropriately to provide sufficient strength to the joint and / or to produce the desired length of the combined tire carcass ply.

[0029] The first end portion may be the first longitudinal surface of the tire base layer of the first length, the second end portion may be the second longitudinal surface of the tire base layer of the second length, and forming a contact area between the first end portion and the second end portion may include abutting the first end portion against the second end portion.

[0030] By abutting the longitudinal end faces, the materials do not overlap in the thickness direction. The end faces of the first pair of reinforcing elements may abut against the end faces of the second pair of reinforcing elements.

[0031] The first longitudinal end and the second longitudinal end of the length of the tire base layer may have complementary shapes such that when the first end portion and the second end portion of the length of the tire base layer are abutted, a continuous tire base layer with parallel side faces is produced.

[0032] Thus, the longitudinal end of the tire base layer of the first length can fit into the adjacent face of the tire base layer of the second length. Thus, a smooth transition from the tire base layer of the first length to the tire base layer of the second length is formed, reducing the visibility of the joint. The contact area between the end faces is also maximized by having corresponding shapes that allow continuous contact between the faces.

[0033] The first longitudinal end and the second longitudinal end may be formed as a single length perpendicular to the length of the tire base layer, each may be formed as a plurality of lengths perpendicular to the length of the tire base layer, may be formed non-perpendicular to the length of the tire base layer, or may be formed as a curve or a plurality of curves.

[0034] Thus, both ends may be formed as a straight line along the lateral direction of the tire base layer. Both ends may be formed as a diagonal line of a straight line at an angle to the lateral direction of the tire base layer. One end may have a stepped or notched shape with a portion that protrudes further than another portion, and the other end may have a reverse stepped or notched shape with a portion that receives the protruding portion of the first end portion. One end may be provided with a concave curve, and the other end may be provided with a reverse convex curve.

[0035] The reinforcing elements may extend longitudinally from the first end portion and / or the second end portion of the tire base layer of the respective first length and the tire base layer of the second length such that the reinforcing elements abut and / or overlap when the contact region is formed.

[0036] Each reinforcing element can be connected without interference or overlap of the tire base layer material.

[0037] Joining the first end portion and the second end portion to each other may include placing an insert between the longitudinal plane of the tire base layer of the first length and the longitudinal plane of the tire base layer of the second length.

[0038] Thus, the insert separates at least a portion of the first end face from the second end face. The insert may be an adhesive to assist in joining. The first longitudinal end and the second longitudinal end may be complementary in shape to fit together as described above, or the first longitudinal end and the second longitudinal end may have non-complementary shapes, and the insert may be shaped to ensure that the ends are joined such that a continuous tire base layer with parallel side faces is produced.

[0039] The insert may comprise a head portion that extends at least partially across the first end portion and the second end portion.

[0040] Thus, the insert is provided between the end faces and on and / or under at least a portion of the tire base layer. The additional contact area between the insert and the tire base layer provided by the head portion increases the strength of the joint. The head portion of the insert may extend across the major portion of the tire base layer of the first length and / or the tire base layer of the second length.

[0041] The reinforcing elements may extend longitudinally from the first end portion and / or the second end portion of each of the first length tire ply and the second length tire ply such that the reinforcing elements contact and / or overlap when the insert is disposed between the longitudinal faces of the first length tire ply and the longitudinal faces of the second length tire ply.

[0042] Accordingly, the reinforcing elements may extend through the insert. Accordingly, the connection of the reinforcing elements may be made to improve stress transfer along the tire ply.

[0043] The reinforcing elements of the first pair of reinforcing elements may be joined to the corresponding reinforcing elements of the second pair of reinforcing elements via a sleeve, seam, welding, solder or glue.

[0044] The joint between the reinforcing elements may be between the tips of the longitudinally overlapping reinforcing elements, or between the sides of the end portions of the transversely or thicknesswise overlapping reinforcing elements. At least one of the pairs of reinforcing elements may extend beyond the base material of each length of the tire ply so as to overlap with the corresponding reinforcing elements of the other pair. When a seam is used to join the reinforcing elements, the seam may be formed using a device such as a bartack machine or an automatic rope machine.

[0045] The reinforcing elements may be composed of metal, and the reinforcing elements may be joined via spot welding. The reinforcing elements may be composed of a thermoplastic material, and the reinforcing elements may be joined by heat treatment.

[0046] The joint between the first pair and the second pair of reinforcing elements allows stress to be conducted through the connected pair.

[0047] A sleeve of additional material may be disposed around the joint of the reinforcing elements. The sleeve may be applied over a joint that may have been formed by welding, soldering and / or gluing.

[0048] The method may include bonding a liner material to a first length of tire carcass and a second length of tire carcass such that the liner material overlaps a joint between the first end portion and the second end portion.

[0049] Accordingly, the liner material supports the joint. The liner material need not extend around all edges of the tire carcass and may cover a portion of the joint. Optionally, the liner material may be bonded to the first length of tire carcass and the second length of tire carcass via an adhesive or glue. The liner may extend at least 0.5 cm along the longitudinal length of the tire carcass. The liner may extend from one longitudinal face of the tire carcass to the opposite longitudinal face of the tire carcass.

[0050] The liner material as well as the first length of tire carcass and the second length of tire carcass may include fibers, and the liner material is bonded to the first length of tire carcass and the second length of tire carcass such that the fibers of the liner material are aligned with the fibers of the first length of tire carcass and the second length of tire carcass.

[0051] Optionally, the fibers of the liner material may be aligned with the fibers of the first length of tire carcass and the second length of tire carcass within an angular range of 15 degrees or less. The first length of tire carcass and the second length of tire carcass may each include a first set of fibers and a second set of fibers arranged at two different angles with respect to the longitudinal length of the tire carcass, and the liner material may include two sets of fibers oriented in a manner corresponding to the fibers of the first length of tire carcass and the second length of tire carcass, and the liner material may be bonded to the first length of tire carcass and the second length of tire carcass such that each of the first set of fibers and the second set of fibers of the liner material is aligned with the first set of fibers and the second set of fibers of the length of the tire carcass. The high tensile strength of the fibers aids in resisting tensile stress, and aligning the fibers of the liner and the tire carcass enables stress propagation along the high tensile strength fibers.

[0052] The liner material may include fibers such that when joined to a tire base layer of a first length and a tire base layer of a second length, the liner material includes fibers aligned with the longitudinal length of the tire base layer.

[0053] Accordingly, the liner material includes fibers aligned in the direction of the reinforcing elements to assist in the transfer of force between the reinforcing elements of the tire base layer of the first length and the reinforcing elements of the tire base layer of the second length.

[0054] The liner material may be disposed on the lower surfaces of the first major portion and the second major portion.

[0055] That is, the joined tire base layer is formed cylindrically for use in a tire, and the liner is disposed radially inward of the tire base layer. Accordingly, the height difference caused by the liner does not affect the tread of the tire.

[0056] The liner material may extend continuously from the lower surfaces of the first major portion and the second major portion, beyond the longitudinal edges of the length of the base layer, to the upper surfaces of the base layer of the first length and the base layer of the second length.

[0057] Accordingly, when the joined tire base layer is formed into a cylindrical tire having a double-curved shape for use in a tire, the liner is disposed on the radially inner surface of the tire base layer with respect to a radius r in a cross-section, and extends radially outward of the tire base layer of the first length and the tire base layer of the second length with respect to the radius r of the circumferential plane of the tire.

[0058] The liner material is disposed at a predetermined position on the joint before joining the first end portion and the second end portion.

[0059] Accordingly, in related embodiments, the liner is present when performing a welding operation. Accordingly, in related embodiments, the liner material is present when increasing the temperature of the contact region between the first end portion and the second end portion and applying pressure, and / or when vibrating the contact region between the first end portion and the second end portion and applying pressure.

[0060] The method may include performing the method of the first aspect according to any of the above descriptions a sufficient number of times to create a circular loop of the tire ply.

[0061] In some cases, the tire ply of the first length and the tire ply of the second length are continuous, i.e., belong to a single strip of the tire ply, and the method of joining the first end portion and the second end portion needs to be performed only once to form a complete circle of the tire ply for use in a tire. In other cases, the tire ply of the first length and the tire ply of the second length are separate, and thus additional joining including additional end faces is required to form a complete loop for use in a tire. Thus, tire plies of the first length and the second length of many sizes can be used to provide a ply for a tire having a desired circumference.

[0062] The tire ply of the first length and the tire ply of the second length may include a double-curved tire shape, and the double-curved tire shape has a radius r in the cross section and a radius of curvature R in a section perpendicular to the cross section.

[0063] Thus, during the joining operation, the tire ply may include a shape corresponding to the shape adopted when used within the tire. Alternatively, the tire ply may be joined when flat and then modified to have a double-curved tire shape. The shape of each of the tire ply of the first length and the tire ply of the second length may include a segment of a cylindrical tire.

[0064] The method may include applying heat to the tire ply and stretching the tire ply on the surface of the wheel so that the tire ply adopts a double-curved tire shape.

[0065] Heat enables the tire carcass to be malleable such that it plastically deforms when the tire carcass is stretched onto the wheel. The tire carcass is cooled so that the curvature adopted when the tire carcass is stretched onto the wheel is maintained by the tire carcass.

[0066] Stretching the tire carcass onto the wheel can be performed in a continuous process such that a continuous belt of the tire carcass is supplied onto the wheel and can be removed from the wheel without cutting the tire carcass.

[0067] Forming the tire carcass can reduce the complexity and / or increase the efficiency of further processes for forming a tire having the tire carcass.

[0068] Providing a double-curved shape to each of the first length of tire carcass and the second length of tire carcass may include providing a length of tire carcass in a substantially flat shape, the substantially flat shape including at least one depression and at least one ridge, each depression and ridge extending in both the transverse and longitudinal directions of the tire carcass and being inclined.

[0069] The substantially flat shape enables easier handling due to its compact form, for example enabling continuous processing steps. The method may include inverting the depression to generate a double-curved shape having a radius r in the transverse direction and a radius R in the longitudinal direction.

[0070] The length of the tire base layer including the double-curved tire shape can be manufactured by providing the length of the tire base layer, inserting the length of the tire base layer into the cavity of the base mold, and applying heat and pressure. The base mold is a substantially flat mold comprising a housing with at least one longitudinal internal cavity extending between at least two opposing main walls and two opposing edge walls. Each of the main walls has at least one ridge and at least one depression, and each ridge and each depression extend and slope in both the transverse and longitudinal directions of the cavity. The ridges and depressions are alternately arranged along the length of the mold, and the ridges of one main wall face the depressions of the other main wall.

[0071] Heat and pressure conform the tire base layer to the shape of the substantially flat mold.

[0072] The length of the tire base layer including the double-curved tire shape can be manufactured by providing the length of the tire base layer, inserting the length of the tire base layer into the cavity of the base mold, and applying heat and pressure. The shape of each of the first length tire base layer and the second length tire base layer includes a segment of a cylindrical tire.

[0073] The shape of the cavity of the tire base mold may correspond to a segment of a circle. The segment may be 45 degrees or less, 45 degrees or more, 90 degrees or more, 180 degrees or more (i.e., a semi-circle) or more, 270 degrees or more.

[0074] The shape of the cavity of the tire base mold may include a plurality of segments of a cylindrical tire. The arc of each of the plurality of segments may extend along the longitudinal length of the cavity, and the midpoints of at least one pair of adjacent segments may extend in the same transverse direction with respect to the longitudinal length of the cavity, thereby forming a bump-like pattern.

[0075] Additionally or alternatively, the arcs of each of the plurality of segments may extend along the longitudinal length of the cavity, and the midpoints of at least one pair of adjacent segments extend in a transverse direction opposite to the longitudinal length of the cavity, thereby forming a sinusoidal pattern. Thus, the mold is flattened with respect to a curve having a radius R in a cross-section perpendicular to the longitudinal direction of the cylindrical tire, thereby reducing the size and complexity of the mold.

[0076] The tire base layer of the first length and / or the tire base layer of the second length may include a tread.

[0077] The tread on the tire base layer of the first length may be joined to the tread on the tire base layer of the second length, which can be achieved using a joining process for joining the tire base layers. Alternatively, additional steps may be required to join the treads.

[0078] The tread may be an overmolded tread, i.e., the tread may be disposed on the tire base layer of the first length and the tire base layer of the second length by injection molding before the joining step is performed.

[0079] The tread may be an overmolded tread and may be provided by inserting the length of the tire base layer into the tread mold, injecting an elastomeric material into the tread mold, curing the elastomeric material so that the elastomeric material and the tire base layer adopt the shape of the tread mold, and removing the joined tire base layer and elastomeric material from the tread mold.

[0080] The tread mold may be a substantially flat tread mold comprising a housing having at least one longitudinal internal cavity extending between at least two opposing main walls and two opposing edge walls, each of the main walls having at least one ridge and at least one depression. Each ridge and each depression extend and slope in both the transverse and longitudinal directions of the cavity, the ridges and depressions being alternately arranged along the length of the tread mold, with the ridges of one main wall facing the depressions of the other main wall.

[0081] The joining process may be performed while the tire carcass and the overmolded tread are in a substantially flat shape. Alternatively, the method provides an overmolded tread on the tire carcass using a substantially flat tread mold as described above, and prior to joining a first length of the tire carcass and a second length of the tire carcass, inverting the depressions to create a double-curved shape having a radius r in the transverse direction and a radius R in the longitudinal direction.

[0082] The first length and / or the second length of the tire carcass may have a double-curved shape, and the dimensions of the depressions and ridges of the tire carcass are larger than the dimensions of the depressions and ridges of the tread mold.

[0083] Accordingly, when a substantially flat tire carcass and a substantially flat tread mold are used, the dimensions are different between the molds such that the dimensions of the molded tire carcass are larger than the equivalent dimensions of the molded tread. Due to the difference in the thermal expansion of the material of the tire carcass and the thermal expansion of the tread material, following the deposition of the tread on the carcass and subsequent cooling, the curvatures of the carcass and the tread are matched. Accordingly, the difference in the thermal expansion of different materials is taken into account.

[0084] The shape of the cavity of the tread mold may include at least one segment of a cylindrical tire.

[0085] The shape of the cavity of the tread mold may correspond to a segment of a circle. The segment may be 45-degree segment or less, may be 45-degree segment or more, may be 90-degree segment or more, may be 180-degree segment (i.e., semi-circle) or more, or may be 270-degree segment or more.

[0086] The shape of the cavity of the tread mold may include a plurality of segments of a cylindrical tire. Each arc of the plurality of segments may extend along the longitudinal length of the cavity of the tread mold, and the midpoints of at least one pair of adjacent segments may extend in the same lateral direction with respect to the longitudinal length of the cavity, thereby forming a bumpy pattern. Additionally or alternatively, each arc of the plurality of segments may extend along the longitudinal length of the cavity of the tread mold, and the midpoints of at least one pair of adjacent segments may extend in the opposite lateral direction with respect to the longitudinal length of the cavity, thereby forming a sine wave pattern. Thus, the tread mold reduces the dimensions and complexity of the tread mold by flattening the mold with respect to a curve having a radius R in a cross-section perpendicular to the longitudinal direction of the cylindrical tire.

[0087] The tire base layer of the first length and the tire base layer of the second length may have a double-curved tire shape, and the radius of curvature adopted by the tire base layer of the first length and the tire base layer of the second length may be larger than the radius of curvature of the cavity of the tread mold.

[0088] Thus, the radius of curvature of the tire base layer of the first length and the tire base layer of the second length is larger than the radius of curvature of at least one segment of the tread mold. That is, the lateral and longitudinal ranges of at least one segment of the tire base layer are larger than the lateral and longitudinal ranges of at least one segment within the tread mold. Thus, at least one segment of the tire base layer has dimensions larger than at least one segment of the tread mold into which it is inserted.

[0089] The first end portion, the first main portion, and the second main portion may include a tread, the second end portion does not include a tread, and joining the first end portion and the second end portion may include joining the tread of the first end portion to the tread of the second main portion and / or joining the tread of the first end portion to the tire ply of the second end portion.

[0090] The ply of the second end portion may overlap the first end portion such that the tread of the second main portion is adjacent to or abuts the tread of the first end portion. The tread may be joined by overmolding an additional elastomeric material onto the exposed tire ply of the first end portion. Alternatively, the tread may be joined by any of the joining processes described above with respect to the joining of the tire ply.

[0091] The tread of the first end portion may extend beyond the tire ply of the first end portion in the longitudinal direction of the tire ply.

[0092] The tread extending beyond the tire ply of the first end portion may be joined to the ply of the second end portion. The tread may extend more than 1 cm beyond the tire ply. The tread may extend up to 5 cm beyond the tire ply. When an insert is used, the tread of the first end portion may extend beyond the insert. The tread and / or insert extending beyond the ply of the first end portion may have a length such that the treads of the first end portion and the second end portion can be joined and the tire plies of the first end portion and the second end portion can be joined.

[0093] The first main portion and the second main portion may include a tread, the first end portion and the second end portion may not include a tread, and joining the first end portion and the second end portion may include at least partially overlapping the first end portion and the second end portion and applying a material between the first main portion and the second main portion to cover the first end portion and the second end portion.

[0094] The material applied between the first main part and the second main part may be applied by overmolding an elastomeric material onto the exposed tire substrate. The material applied between the first main part and the second main part may penetrate the tire substrate such that the elastomeric material extends from one side of the tire substrate of the first end part and the second end part to the opposite side of the first tire end part and the second tire end part. Particularly good penetration occurs when the tire substrate consists of a mesh and / or fabric.

[0095] The first length of tire substrate and the second length of tire substrate each provide a sheet of material having a first side edge portion and a second side edge portion, the first side edge portion being separated from the second side edge portion by a central portion, placing a first reinforcing element on the sheet where the first side edge portion intersects the central portion, placing a second bead wire on the sheet where the central portion intersects the second side edge portion, folding the first side edge portion over the first reinforcing element, folding the second side edge portion over the second reinforcing element, and fixing the first side edge portion and the second side edge portion to the central portion.

[0096] This method enables the formation of a substrate including reinforcing elements in a continuous process. The substrate including reinforcing elements may be formed into a flat piece that need not have a length corresponding to the circumference of the tire. Instead of using the above method, a long substrate having a length many times the circumference of the tire that can be cut to the appropriate size as required can be produced.

[0097] Providing a continuous belt of the substrate enables the substrate to be incorporated into a continuous process for forming a tire.

[0098] The first length of substrate and / or the second length of substrate may be provided in the form of a continuous belt of tire substrate.

[0099] Therefore, the joining of the two base layer end portions can be incorporated into a continuous manufacturing process.

[0100] Viewed from another aspect, the present invention provides a tire manufactured according to a method for manufacturing the above-described tire base layer and overmolded tread.

[0101] The tire can be suitable for any transport device including a wheel. The tire can be suitable for a bicycle or tricycle, a motorcycle, a scooter and an automobile such as a large truck or a baby carriage.

[0102] Viewed from another aspect, the present invention is an apparatus for joining a first length of a tire base layer and a second length of a tire base layer, the apparatus comprising a clamp for positioning a first end portion of the first length of the tire base layer and a second end portion of the second length of the tire base layer and performing a welding operation for joining the first end portion and the second end portion.

[0103] Thus, in related embodiments, the apparatus for joining a first length of a tire base layer and a second length of a tire base layer is configured to apply one or more of pressure and heat and vibration to the first end portion and the second end portion. The heat may be applied from an external heat source, and / or the heat may be generated by mechanical movement, and / or the heat may be generated using electricity magnetism.

[0104] The apparatus may comprise means for cutting a continuous belt of the tire base layer to a desired length for the first length of the tire base layer and / or the second length of the tire base layer.

[0105] The apparatus may include an overmold station comprising means for simultaneously positioning the first end portion and the second end portion of the tire base layer in an at least partially overlapping configuration and injecting an elastomeric material between the first major portion and the second major portion of the tire base layer.

[0106] Next, specific embodiments of the present invention will be described by way of example only with reference to the accompanying drawings.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0108] As seen in FIG. 1, a pair of bead wires 12 are disposed on a sheet of base layer material 10, each being aligned with the longitudinal length of the sheet 10. Thus, the sheet 10 includes a first side edge 14 defined by the bead wire 12, a central portion 16, and a second side edge 18.

[0109] FIG. 2a shows a sheet of tire base layer material formed on a tire base layer comprising a stiffening element by folding the first side edge 14 over the first bead wire 12a and the second side edge 18 over the second bead wire 12b. The first side edge 14 and the second side edge 18 overlap to form an overlapping region 22. The first side edge 14 and the second side edge 18 can be fixed to the central portion 16. In the overlapping region 22, the first side edge 14 and the second side edge 18 can also be fixed to each other. Since the pair of bead wires 12 are arranged parallel to each other, the first longitudinal side portion 24 and the second longitudinal side portion 28 of the tire base layer comprising the stiffening element 20 are also parallel to each other. The first side edge 14 and the second side edge 18 do not necessarily need to overlap to form the overlapping region 22. FIG. 2b shows an example where the first side edge 14 and the second side edge 18 are fixed only to the central portion.

[0110] Figure 3a shows the folding of the sheet of the base layer material 10 performed by the folding device 30. The related reference numerals provided in FIGS. 1 and 2 are reproduced in FIG. 3a. The sheet 20 of the base layer material is supplied to the folding device 30 at the first end 32 and is moved in the direction A along the folding device 30. The first folding device 31 includes a first folding guide 34. The first folding guide 34 biases the first side edge 14 to bend or fold around the first bead wire 12a and guides the first side edge 14 to a position adjacent to or in contact with the central portion 16. Further along the folding device 30, in the direction A, a second folding device 33 is provided. The second folding device 33 includes a second folding guide 38 that biases the second side edge 18 to bend or fold around the second bead wire 12b and guides the second side edge 18 to a position adjacent to or in contact with the central portion 16 and / or a position adjacent to or in contact with the first side edge 14 in the overlapping region 22.

[0111] When the sheet 20 of the base layer material is supplied through the folding device 30, the creation of the tire base layer with the stiffening element 20 can be continuously carried out. In this way, a continuous belt of the tire base layer can be formed. This means that a tire base layer with sufficient stiffening elements 20 for use in a plurality of tires can be formed without manual intervention. The tire base layer with the stiffening element 20 exiting the second folding device 33 can be wound onto a spool for storage.

[0112] The first folding device 31 also includes fixing means (not shown) for fixing the first side edge 14 to the central portion 16. Similarly, the second folding device 33 includes fixing means (not shown) for fixing the second side edge 18 to the central portion 16 and / or the first side edge 14. For example, the fixing means of the first folding device 31 and / or the second folding device 33 may include a heat gun.

[0113] Figure 3b shows a base layer material spool 35, a first bead wire spool 36a, and a second bead wire spool 36b. The sheet 10 of the base layer material is directly supplied from the base layer material spool 35 to an assembly unit including a folding device 30. Similarly, the first bead wire 12a and the second bead wire 12b are directly supplied from the first bead wire spool 36a and the second bead wire spool 36b to the folding device 30, respectively. A fixing device (not shown) can be used to fix the bead wires 12a and 12b at predetermined positions on the sheet of the base layer material before starting the folding operation.

[0114] Figure 3c shows an assembled tire base layer including a reinforcing element 20 and a reinforcing element 61 wound on a spool 38 for storage. The tire base layer including the reinforcing element 20 may be wound around the spool 38 directly from the folding device 30 or after further manufacturing steps such as the application of overmolding as described below. The tire base layer including the reinforcing element 61 formed using a tubular material to be further described below can also be wound around the spool 38 immediately after assembly or after further manufacturing steps.

[0115] The continuous belt of the tire base layer including the reinforcing element 20 can be pulled out from the spool and cut to a desired length for further processing for use in a tire. The continuous belt of the tire base layer including the reinforcing element 20 can be directly pulled out from the spool to a further device for processing the continuous belt of the tire base layer including the reinforcing element 20 for use in a tire. In this way, the processing can be continuously maintained.

[0116] The continuous belt of the tire base layer including the reinforcing element 20 can instead be directly supplied from the folding device 30 to a further device for processing the continuous belt of the tire base layer including the reinforcing element 20 for use in a tire. Similarly, in this way, the processing can be continuously maintained.

[0117] Figure 4 shows a sheet 10 of a material having a fiber structure. The fibers of the fiber structure may be formed from nylon, cotton, polyester, or aramid. The fiber structure includes a unidirectional fiber set 40 (the diagonal hatching indicates the presence and direction of the first fiber set), and each fiber of the set 40 extends in a direction substantially parallel to the other fibers of the set 40. The unidirectional fiber set 40 is supported by a set of support fibers (not shown) woven through the unidirectional fiber set 40 to fix the fibers to each other.

[0118] The sheet 10 of the material is cut such that the direction of the unidirectional fiber set 40 is misaligned by an angle α with respect to the longitudinal direction of the sheet.

[0119] Figure 5 shows a tire base layer having a stiffening element 20 when the first side edge 14 is folded over the first bead wire 12a and the second side edge 16 is folded over the second bead wire 12b. As shown by the hatching, the direction of the unidirectional fiber set 40 in the central portion 16 is different from the direction of the unidirectional fiber sets at the first side edge and the second side edge. In other words, the base layer material provided between a pair of bead wires 12 in the tire base layer having the stiffening element 20 includes fibers in different directions.

[0120] Figure 6a shows a cross-section of a tire base layer having a stiffening element 20 taken perpendicular to its longitudinal length. The first side edge 14 is folded around the first bead wire 12a and fixed to the central portion 16. The second side edge is folded around the second bead wire 12b and fixed to the central portion 16 and the first side portion 14 within the overlapping region 22.

[0121] Figure 6b shows a cross-section similar to Figure 6a for an example where the first side end 14 and the second side end 18 do not form an overlapping region 22.

[0122] Figures 7a to 7c similarly show cross-sections of a tire base layer with a stiffening element 20 taken perpendicular to its longitudinal length. Each of Figures 7a to 7c shows a puncture protection layer 50. In each case, the puncture protection layer 50 is provided in the middle part 52 of the tire base layer with the stiffening element 20. When the tire base layer is used within a tire, the middle part 52 of the tire base layer with the stiffening element 20 coincides with the tread of the tire, and the first side part 54 and the second side part 58 of the tire base layer with the stiffening element 20 coincide with the sidewalls of the tire. The middle part 52 is arranged adjacent to the ground contact area of the tire. Therefore, the puncture protection layer 50 is arranged so as to at least coincide with the tread of the tire in order to provide the most useful protection.

[0123] Figure 7a shows a puncture protection layer 50 provided on the outer surface of the first side part 14 and / or the second side part 18.

[0124] Figure 7b shows a puncture protection layer 50 provided between the central part 16 and the first side part 14 and / or the second side part 18.

[0125] Figure 7c shows a puncture protection layer 50 provided on the outer surface of the central part 16.

[0126] For an example where the first side end part 14 and the second side end part 18 do not form an overlapping area 22 as shown in Figure 6b, the puncture protection layer 50 can be provided at corresponding positions as shown in Figures 7a to 7c.

[0127] Figure 8 shows a puncture protection layer 50 provided in the folding device 30. In this example, the puncture protection layer can be incorporated between the overlapping parts of a sheet of the base layer material, or can be fixed to the sheet 10 using the steps described herein.

[0128] FIG. 9 shows a tubular material 60 used to manufacture a continuous belt of a tire base layer. The tubular material 60 extends in the longitudinal direction, and during the manufacture of the continuous belt of the tire base layer, the first stiffening element 12a and the second stiffening element 12b are inserted into the tubular material 60 so as to extend in the same longitudinal direction. Accordingly, the first stiffening element 12a and the second stiffening element 12b extend parallel to the longitudinal length of the tubular material 60. Tubular means that the material provides a cylinder with a hollow center, and thus, it means that the stiffening elements 12a, 12b are inserted into the hollow center. The tube configuration of the tubular material may be created simultaneously with the insertion of the stiffening elements into the center of the tubular material so as to enable the continuous manufacture of a tire base layer comprising the stiffening elements 61 (by fixing a first longitudinally extending edge to a second longitudinally extending edge, or by weaving the material, etc.).

[0129] FIG. 10 shows the tubular material once flattened. To maintain the flat shape, the tubular material on the first side 62 (e.g., upper) of the first stiffening element 12a and the second stiffening element 12b is fixed to the tubular material on the second side 64 (e.g., lower) of the first stiffening element and the second stiffening element. The first side 62 and the second side 64 are on opposite sides of the stiffening elements 12a, 12b.

[0130] FIG. 11 shows a cross-section of a tire base layer comprising a stiffening element 61 taken perpendicular to its longitudinal length. The tubular material on the first side 62 (e.g., upper) of the first stiffening element 12a and the second stiffening element 12b is fixed to the tubular material on the second side 64 (e.g., lower) of the first stiffening element and the second stiffening element.

[0131] Figures 12a and 12b similarly show a cross-section of a tire base layer with a stiffening element 61 taken perpendicular to its longitudinal length. Each of Figures 12a and 12b shows a puncture protection layer 50. In each case, the puncture protection layer 50 is provided in the middle part 66 of a tubular tire base layer with a stiffening element 61. When the tire base layer is used within a tire, the middle part 66 of the tire base layer with a stiffening element 61 coincides with the tread of the tire, and the first side part 67 and the second side part 68 of the tire base layer with a stiffening element 61 coincide with the sidewalls of the tire. The middle part 66 is arranged adjacent to the ground contact area of the tire. Thus, the puncture protection layer 50 is arranged so as to at least coincide with the tread of the tire in order to provide the most useful protection.

[0132] Figure 12a shows a puncture protection layer 50 arranged radially outside a tubular material 60 when viewed in a cross-section perpendicular to the longitudinal length of the tubular material. The puncture protection layer 50 can be continuously fixed to the belt of the tire base layer. In a later step, the tread may be applied such that the puncture protection layer is between the tread and the tire base layer, or the tread may be applied such that the tire base layer is between the puncture protection layer 50 and the tread.

[0133] Figure 12b shows a puncture protection layer 50 arranged radially inside a tubular material when viewed in a cross-section perpendicular to the longitudinal length of the tubular material. The puncture protection layer can be inserted into the hollow of the tubular material when a tube configuration is created (by fixing a first longitudinally extending edge to a second longitudinally extending edge, or by weaving the material, etc.) so as to enable continuous manufacture of a tire base layer with a stiffening element 20 and the puncture protection layer.

[0134] The creation of the tire base layer with the stiffening element 61 can be carried out continuously. In this way, a continuous belt of the tire base layer can be formed. This means that a tire base layer with the stiffening element 61 sufficient for use in a plurality of tires can be formed without manual intervention. The tire base layer with the stiffening element 61 can be wound onto a spool for storage. The continuous belt of the tire base layer with the stiffening element 61 can be pulled out from the spool and cut to a desired length for further processing for use in a tire. The continuous belt of the tire base layer with the stiffening element 61 can be directly pulled out from the spool to a further device for processing the continuous belt of the tire base layer with the stiffening element 61 for use in a tire. In this way, the processing can be continuously maintained.

[0135] In some examples, the continuous belt of the tire base layer preform is further processed to change the shape of the tire base layer with the stiffening element 20 and the stiffening element 61. The shape is modified to more closely match the shape that the tire base layer has when used within a tire.

[0136] Therefore, the modified shape will have at least some curved aspect reflecting the double-curved tire shape shown in FIG. 13. The double-curved tire shape comprises a curve having a radius of curvature r in the lateral cross-section of a cylindrical tire and a curve having a radius of curvature R in a cross-section perpendicular to the longitudinal cross-section. The double-curved tire shape can also be described as an annular segment having an omega "Ω" cross-section.

[0137] The tire base layer having a double-curved shape comprises a first side wall 74 including a first side portion of the tire base layer 54 and the tire base layer 67, and a second side wall 78 including a second side portion of the tire base layer 58 and the tire base layer 68. The side walls 74 and 78 extend substantially in the radial and circumferential directions around the radius of curvature R. The intermediate portion of the base layers 52 and 66 forms an intermediate wall 72 extending substantially in the circumferential and axial directions around the radius of curvature R.

[0138] The dimensions of the curvature of the tire base layer do not have to match the curvature of the tire and / or the curvature to which the base layer is adapted in the final tire. The curvature imparted to the tire base layer comprising stiffening elements 20, 61 may be less than the final curvature in order to introduce some shaping prior to assembly onto the tire, or the curvature imparted to the tire base layer comprising stiffening elements may be greater than the final curvature in order to compensate for shrinkage that may occur during further processing for assembling the tire.

[0139] The wheel 80 can be used to shape the tire base layer comprising the stiffening elements 20, 61. The tire base layer comprising the stiffening elements 20, 61 is stretched over the surface of the wheel 80 and heat is applied to curve the tire base layer comprising the stiffening elements 20, 61. As shown in FIG. 14, the surface of the wheel 80 has a radius of curvature r in a transverse cross-section and a radius of curvature R in a cross-section perpendicular to the transverse cross-section, and thus the tire base layer comprising the stiffening elements 20, 61 stretched over this wheel is given a double-curved tire shape. The resulting shaped tire base layer comprising the stiffening elements 20, 61 can be manipulated into a substantially flat shape to facilitate further use by inverting portions of the tire base layer comprising the stiffening elements 20, 61 to create longitudinal and transverse recesses and protrusions as can be seen in FIG. 21.

[0140] The tire base layer comprising the stiffening elements 20, 61 can be shaped into a double-curved tire shape using a segment mold 90 comprising a cavity 92 with at least a segment of a double-curved tire shape. Such a segment mold 90 is shown in FIG. 15. The tire base layer comprising the stiffening elements 20, 61 is provided as a belt of a continuous tire base layer and can be drawn into the cavity 92, and the upper 94 and lower 96 portions of the segment mold are closed to compress the tire base layer comprising the stiffening elements 20, 61 within the cavity 92 and heat and pressure are applied.

[0141] The molded tire base layer obtained after molding using this segment mold 90 is shown in FIG. 16. The cavity 92 and the molded tire base layer have a curvature r in the cross section and a radius R in the cross section perpendicular to the cross section.

[0142] An alternative segment mold 90 is shown in FIG. 17, and the cavity 92 comprises a plurality of segments. The molded tire base layer with stiffening elements obtained from this mold can be further manipulated (e.g., bent or stretched) to remove the joints between the segments and form a continuous curvature.

[0143] FIG. 18 shows a cross section (a cut plane passing through the center of the mold) of a substantially flat tire base layer mold 100 used to pre-mold a tire base layer with stiffening elements 20 and 61. The cavity 101 created between the upper piece 102 and the lower piece 103 comprises recesses and protrusions extending in the transverse direction and the longitudinal direction of the cavity 101.

[0144] FIG. 19 shows the lower piece 103 of a substantially flat tire base layer mold 100 having a plurality of recesses and protrusions.

[0145] FIG. 20 shows a contour map of the recesses and protrusions along the substantially flat tire base layer mold 100. The protrusions and recesses in the longitudinal direction of the cavity of the substantially flat tire base layer mold are shown along line L-L. 104 indicates a peak and 105 indicates a trough. The transverse recesses are shown along line t 1 -t 1 and decrease from the high point 106 to the trough 105 and then increase to another high point 106. The transverse protrusions are shown along line t 2 -t 2 and increase from the low point 107 to the peak 104 and then decrease to the low point 107.

[0146] When a tire base layer with stiffening elements is removed from a substantially flat tire base layer mold 100, the recesses are reversed, i.e., inverted, such that the tire base layer with stiffening elements follows a single curvature in the longitudinal direction of the tire base layer with stiffening elements. The curvatures provided by the recesses and protrusions are thus summed such that they form a segment of a circle when the recesses are reversed. Similarly, the lateral recesses and protrusions are here adapted to complementary curvatures to form the side walls of the segment of the circle and form an "Ω" shaped cross-section.

[0147] Put another way, the curvature adapted to a tire base layer with stiffening elements 20, 61 in the lateral direction helps to form the side walls of the base layer within the tire and thus the "Ω" cross-section. The curvature adapted to a tire base layer with stiffening elements 20, 61 in the longitudinal direction of the base layer helps to form the tire annular loop.

[0148] Figure 21 shows a tire base layer with stiffening elements 20, 61 preformed to have a substantially flat shape with recesses and protrusions in the longitudinal and transverse directions.

[0149] In some examples, a substantially flat molded tire base layer with stiffening elements is stored having the foregoing configuration and can be used in a further process for forming a tire at a later time. In some examples, a substantially flat molded tire base layer with stiffening elements is used directly in a further process for forming a tire, and the inversion of the recesses and protrusions is performed subsequent to subsequent processing steps.

[0150] FIG. 22 shows a cross-section of a tire comprising a base layer formed from the above-described stiffening elements 20, 61. The tire comprises a tread 126 applied to an intermediate wall 72 of the base layer. In some examples, the tread may extend along sidewalls 74, 78 of the tire base layer. An injection molding apparatus is used to apply a tire tread to a tire base layer comprising stiffening elements 20, 61. The injection molding apparatus comprises a tread mold in which a tire base layer comprising stiffening elements 20, 61 is disposed. The tire base layer comprising stiffening elements 20, 61 is disposed within the tread mold for overmolding. An elastomer is injection molded onto the tire base layer comprising stiffening elements 20, 61 to overmold a tread onto the tire base layer comprising stiffening elements 20, 61. In an example where the tire base layer is formed from a sheet of fabric or mesh fabric, the injection molding material penetrates the tire base layer and thus extends from one side of the tire base layer to the opposite side of the tire base layer.

[0151] Regardless of whether the tire base layer with stiffening elements is provided as a belt of a continuous tire base layer (on a spool or otherwise), or as a cross-section cut to a predetermined size of a tire base layer with stiffening elements, and / or provided flat, or preformed as described above, the tire base layer with stiffening elements can be further processed to add a tire tread using overmolding, and examples thereof are provided below.

[0152] FIG. 23 shows an injection molding apparatus 110 that receives directly from a folding apparatus 30 a tire base layer having stiffening elements 20, 61 in the form of a continuous belt of the tire base layer. The cavity of the tread mold 120 can have the substantially flat shape described above with reference to FIGS. 18 - 20 in relation to the tire base layer mold. A substantially flat tread mold is shown below with reference to FIG. 24. The lower half 120a of the substantially flat tread mold 120 is provided on the stationary part of the injection molding apparatus 110, and the upper half 120b of the substantially flat tread mold 120 is provided on the part of the injection molding apparatus movable relative to the stationary part. When half of the tread mold 120 is separated, a continuous belt of the tire base layer is supplied from the folding apparatus 30 and aligned with the lower half of the tread mold 120a. The upper half 120b of the tread mold is moved to close the mold 120, and a thermoplastic material is injected into the cavity of the mold. When the injected thermoplastic material solidifies and conforms to the shape of the cavity of the tread mold, the upper half 120b of the tread mold is moved away from the lower half 120a, and a continuous belt of the tire base layer and the overmolded tread is pulled out of the tread mold. Simultaneously with the movement of the continuous belt of the tire base layer and the overmolded tread, a further tire base layer with stiffening elements included in the continuous belt is drawn from the folding apparatus 30 into the injection molding apparatus 110.

[0153] The continuous belt of the tire base layer can alternatively be supplied from a spool to the injection molding apparatus 110.

[0154] FIG. 24 shows a cross - section of a substantially flat tread mold 120 with a tread pattern 125 on the cavity wall 124 of the lower piece 123.

[0155] FIG. 25 shows a tire base layer having stiffening elements 20, 61 in addition to an overmolded tire tread 126 having a substantially flat shape. The substantially flat shape of the combination of the tread 126 and the tire base layer comprising the stiffening elements 20, 61 is the result of the overmolding step, i.e., the flat belt of the tire base layer can be inserted into the tread mold 120, applying an elastomer to form the tread 126, and applying heat and pressure during the overmolding process, the tire base layer comprising the stiffening elements 20, 61 is adapted to the shape with the recesses and protrusions of the substantially flat tread mold 120. In other examples, the tire base layer with stiffening elements is preformed before entering the substantially flat tread mold 120, and the shape of the tire base layer and the tread after overmolding can be due to the contributions of the tread forming process and the preforming.

[0156] FIG. 26 shows a segment tread mold 130 with a cavity 132 formed as a segment of a double-curved tire shape. FIG. 27 shows a tire base layer with stiffening elements 20, 61 and an overmolded tread 126 formed using the segment tread mold 130 with the double-curved tire shape of the above-mentioned radii r and R. The double-curved tire shape in which the overmolded tread 126 and the tire base layers 20, 61 are combined can be the result of applying an elastomer to form the tread 126 in combination with the application of heat and pressure during the overmolding process. The preformed tire base layer comprising the stiffening elements 20, 61 can be inserted into the segment mold 130, and its molding can contribute to the final shape of the combined tread 126 and the tire base layer comprising the stiffening elements 20, 61.

[0157] FIG. 28 shows a tread mold 140 having a cavity 142 formed as a plurality of segments of a double-curved tire shape. FIG. 29 shows the resulting tire base layer comprising a tread 126 overmolded in addition to stiffening elements 20, 61. The joints between adjacent segments of the base layer and the overmolded tread are manipulated (e.g., bent or stretched) compared to the shape of the cavity of the tread mold 140 to form a continuous curve. The shape shown in FIG. 29 can be further manipulated into a circular tire shape if desired.

[0158] The tire base layer comprising the stiffening elements 20, 61 can be pre-formed as described above, and then the tread is overmolded onto the pre-formed tire base layer. In some examples, the dimensions of the tire base layer are larger than the dimensions of the tread mold. As shown in FIG. 30, when the tire base layer comprising the stiffening elements 20, 61 is pre-formed to have a substantially flat shape, the amplitude and wavelength of the recesses and protrusions are larger than the equivalent amplitude and wavelength of the substantially flat tread mold 120. That is, the change in height between the low points 107 and the peaks 104, between the high points 106 and the troughs 105, and the distance between the peaks 104 and the troughs 105 of the tread mold 120 are smaller than those distances of the pre-formed tire base layer. The tread pattern 125 of the tread mold 120 in FIG. 30 is omitted for clarity.

[0159] The relative differences in the amplitude and wavelength of the recesses and protrusions between the pre-formed tire base layer and the tread mold vary depending on the thermal expansion characteristics of the elastomers of the tire base layer and the tread. In some cases, the amplitude and wavelength of the recesses and protrusions are larger for the substantially flat tread mold 120 than the equivalent amplitude and wavelength of the pre-formed tire base layer. Alternatively, some dimensions may be larger in the substantially flat tread mold and some dimensions may be smaller compared to the pre-formed tire base layer.

[0160] Figure 31 shows a tire base layer 202 of a first length and a tire base layer 212 of a second length. The tire base layer 202 of the first length includes a first end 204, a first main portion 206, and a first pair of supplementary rigid elements 208. The tire base layer 212 of the second length includes a second end 214, a second main portion 216, and a second pair of supplementary rigid elements 218. The ends of the first tire base layer 202 and the ends of the second tire base layer 212 are aligned and joined as shown, such that the supplementary rigid elements of the first pair of supplementary rigid elements 208 and the second pair of supplementary rigid elements 218 are aligned.

[0161] The tire base layer of the first length and the tire base layer of the second length may be flat as shown in Figure 31. Alternatively, the tire base layer of the first length and the tire base layer of the second length may be pre-formed to have a curve. As shown in Figure 32, the tire base layer of the first length and the tire base layer of the second length may be pre-formed to have a double-curved shape, i.e., a curve having a radius of curvature r in the transverse cross-section of the cylindrical tire and a curve having a radius of curvature R in a cross-section perpendicular to the longitudinal cross-section. The double-curved tire shape can also be described as an annular segment having an omega "Ω" cross-section. The base layer has a first sidewall 74, a second sidewall 78, and an intermediate wall 72 as described above.

[0162] The tire base layer 202 of the first length and the tire base layer 212 of the second length can be manufactured by known methods.

[0163] The tire base layer 202 of the first length and the tire base layer 212 of the second length can be made using any of the steps of the above-described method for manufacturing a continuous belt of the tire base layer. Before the joining operation, the continuous belt of the tire base layer can be separated from each other and cut into a tire base layer of the first length and a tire base layer of the second length, each having a predetermined length. Alternatively, before the joining operation, the continuous belt of the tire base layer can be cut into a single piece of a predetermined length and a first piece.

[0164] The tire base layer 202 of the first length and the tire base layer 212 of the second length can be continuous as shown in FIG. 33. That is, the first end 204 and the second end 214 are disposed at the longitudinal ends of a single-piece tire base layer. Thus, a complete loop of the tire base layer is made requiring a single joint.

[0165] In other examples, multiple joints are required to form a complete loop of the base layer suitable for use in a tire. As shown in FIG. 34, the tire base layer 202 of the first length of one joint further provides a tire base layer 212 of the second length for another joint.

[0166] The contact region 220 is formed between the first end 204 and the second end 214. This is shown in FIGS. 35 and 36. In FIG. 35, the contact region 220 is formed by overlapping the first end 204 with the second end 214 to form a tire base layer with double thickness in the contact region 220. In FIG. 36, the contact region 220 is formed by abutting the longitudinal surface 203 of the base layer of the first length (shown in FIG. 31) against the longitudinal surface 213 of the base layer of the second length (shown in FIG. 31).

[0167] Next, a welding operation can be performed in the contact region to fix the tire base layer 202 of the first length and the tire base layer 212 of the second length to each other. The tire base layer 202 of the first length and the tire base layer 212 of the second length can be fixed, additionally or alternatively, by providing an adhesive or an adhesive material between the tire base layer 202 of the first length and the tire base layer 212 of the second length in the contact region.

[0168] In FIG. 37, an example is shown where the first end portion 204 and the second end portion 214 include only the mesh fabric, and the first main portion 206 and the second main portion 216 include the mesh fabric and the elastomer. The contact region 220 (shown in FIG. 38) is formed between at least a part of the first end portion 206 and at least a part of the second end portion 216 by at least partially overlapping the two end portions 204 and 214. Then, the joining of the two end portions 204 and 214 can be performed by overmolding the elastomer over the first end portion 204, the contact region 220, and the second end portion 214. The piece 222 represents the overmolded piece added to the joined base layer when the overmolding process is performed. Thus, the piece 222 extends from the first main portion 206 and joins to the second main portion 216. By ensuring that the ends of the contact region 220 and the joining of the overmolded elastomer with the first main portion 206 and the second main portion 216 are misaligned, a stronger joint can be made by avoiding weaknesses from each aligned joint. However, sufficient results can be obtained by completely overlapping the first end portion 214 and the second end portion 204 to form the contact region 220. Since the mesh fibers have an open structure, the elastomer penetrates the mesh fibers, creating a strong joint by improving both the mechanical bond between the first base layer and the second base layer and the chemical bond between the elastomer and the fibers. Similar advantages can be achieved using this process with other base layer materials that include fibers.

[0169] In particular, when the contact region 220 is created by abutting the longitudinal end faces 203, 213 of the base layer of the first length and the base layer of the second length, the end faces 203, 213 can have complementary shapes as shown in FIGS. 39a - 39d, such that the surfaces engage when joined. In FIG. 39a, the end faces 203, 213 each have a linear shape oriented perpendicular to the longitudinal length of the respective base layer of the first length and the base layer of the second length of the tire. In FIG. 39b, the end faces have a plurality of lengths perpendicular to the length of the tire base layer, and the plurality of lengths form a stepped shape that provides a larger contact surface area between the end faces. The longitudinal end face 203 of the base layer of the first length of the tire has a stepped shape that also has a recess 205, and the longitudinal end face 213 of the base layer of the second length of the tire has a stepped shape that also has a protrusion 215. The protrusion 215 fits into the recess 205. In FIG. 39c, the longitudinal end face 213 of the base layer of the second length of the tire has an expanding chevron shape, and the longitudinal end face 203 of the base layer of the first length of the tire has a cut - out chevron shape. The chevrons are formed by a plurality of lengths that are not perpendicular to the longitudinal length of the tire base layer. In FIG. 39d, the longitudinal end face 213 of the base layer of the second length of the tire has a convex - curved shape, and the longitudinal end face 203 of the base layer of the first length of the tire has a concave - curved shape.

[0170] The insert 230 can be disposed between a tire base layer 202 of a first length and a tire base layer 212 of a second length. The insert 230 shown in FIG. 40a is disposed between an end face 203 and an end face 213. The stiffening elements 12 of the tire base layer 203 of the first length and the tire base layer 213 of the second length are aligned when joined. The insert is fixed to each of the end face 203 and the end face 213 in order to fix the tire base layer 202 of the first length and the tire base layer 212 of the second length to each other. FIG. 40b shows an insert 230 that protrudes over the tire base layer 202 of the first length and the tire base layer 212 of the second length, extends in the lateral and longitudinal directions over the tire base layer 202 of the first length and the tire base layer 212 of the second length, and extends over the end portions 204, 214 and / or the main portions 206, 216, and includes an insert head portion 232.

[0171] FIG. 40c shows an example in which a pair of stiffening elements 12 extend through the insert 230 and can be connected between a first pair of stiffening elements and a second pair of stiffening elements in the tire base layer of the first length and the tire base layer of the second length, respectively.

[0172] FIG. 41a shows an enlarged view of the joint, that is, a view before contact is made and the joint is completed. FIG. 41a shows the stiffening element 208 of the tire base layer 202 of the first length extending from the first end portion 204. The first pair of stiffening elements 208 overlap the second pair of stiffening elements 218 in the longitudinal direction, and thus the tips of the pairs of stiffening elements abut against each other when the joint is made. The tips can then be joined via welding, soldering, stitching or an adhesive. For example, the stitching of aramid stiffening elements may be performed with aramid threads. FIG. 41b shows this situation in a plan view. FIG. 41c shows a similar example in which both the first pair of stiffening elements 208 and the second pair of stiffening elements 218 extend from the first end portion 204 and the second end portion 214, respectively, but the stiffening elements overlap in the lateral direction.

[0173] FIG. 42a shows the joining between a first length of tire base layer 202 and a second length of tire base layer 212, including a liner material 240 joined to a first end 204 and a second end 214.

[0174] FIG. 42b shows an example in which the first length of tire base layer 202 and the second length of tire base layer 212 are formed in a doubly curved shape. FIG. 42c shows an enlarged view of FIG. 42b (i.e., where no contact and joining are taking place) showing the position and extent of the liner material 240 around the joint. The liner material 240 extends from the radially outer surface (not shown) of the first sidewall 74 with respect to the radius of curvature r, to the radially inner surface 73 of the first sidewall 74 with respect to the radius of curvature r, along the radially inner surface 72a of the intermediate wall 72 with respect to the radius of curvature r, along the radially inner surface (not shown) of the second sidewall 78, and to the outer surface 77 of the second sidewall 78.

[0175] The liner 240 can extend around the entire joint and can be considered a sleeve. The sleeve 240 can be tight enough to fix the first length of tire base layer 202 and the second length of tire base layer 212 to each other and / or can be provided with an adhesive. In some examples, the liner 240 includes fibers that provide additional strength.

[0176] FIG. 43 shows an example in which the liner 240, the first length of tire base layer 202, and the second length of tire base layer 212 include fibers. The fiber direction of each component is shown in the figure by the direction of the cross-hatching. The fiber direction of the liner 240 is substantially aligned with the fiber directions of the first length of tire base layer 202 and the second length of tire base layer 212. In some examples, the liner 240 additionally or alternatively includes fibers that extend in the longitudinal direction of the first length of tire base layer 202 and the second length of tire base layer 212. It will be understood that the liner and / or the first and second lengths of tire base layer may further include fibers that extend in a direction different from the direction shown in FIG. 43.

[0177] In FIG. 44a, the tire base layer 202 of the first length includes the first tread portion 252, and the tire base layer 212 of the second length includes the second tread portion 254. The first tread portion 252 is disposed above the first main portion 206 of the tire base layer 202 of the first length on the intermediate wall 72, but does not extend over the first end portion 204. The second tread portion 254 is disposed above both the second main portion 216 and the second end portion 214. When joining is performed according to any of the above descriptions, the first end portion is disposed under (radially inward) the second end portion such that the first tread portion 252 abuts the second tread portion 254.

[0178] In FIG. 44b, the first tread portion 252 extends across both the first main portion 206 and the first end portion 204, and the second tread portion 254 extends across the second main portion 216 and the second end portion 214. The contact region 220 is provided by the longitudinal end faces of the tire base layer of the first length, the tire base layer of the second length, and the tread portions such that the tire base layer of the first length and the tire base layer of the second length are fixed to each other and the first tread portion and the second tread portion are fixed to each other.

[0179] In an example where the insert 230 is used, the insert can include an insert tread portion 234 provided on or instead of the insert head portion 232.

[0180] FIG. 45 shows a joining device 260 used for joining the tire base layer 202 of the first length and the tire base layer 212 of the second length. The joining device includes a clamp 262 for maintaining the tire base layer of the first length and the tire base layer of the second length in a predetermined position so that the end portions 204 and 214 can be properly joined. The joining device shown in FIG. 45 is configured to apply heat and pressure between an upper clamp surface 264 and a lower clamp surface 266 to form a joint.

Claims

1. A method of providing a joint between a first tire base layer end portion and a second tire base layer end portion, the method comprising: providing a first length of tire base layer having a first end portion, a first main portion, and a first pair of reinforcing elements; providing a second length of tire base layer having a second end portion, a second main portion, and a second pair of reinforcing elements; joining the first end portion and the second end portion to each other such that each of the reinforcing elements of the first pair of reinforcing elements is aligned with a corresponding reinforcing element of the second pair of reinforcing elements.

2. The method of claim 1, wherein the first pair of reinforcing elements includes a first pair of bead wires and the second pair of reinforcing elements includes a second pair of bead wires.

3. The method of claim 1 or 2, wherein the first length of tire base layer and the second length of tire base layer are continuous such that the first end portion and the second end portion are opposing longitudinal ends of a single tire base layer.

4. The method of claim 1, 2, or 3, including joining the first end portion to the second end portion via a sleeve, seam, weld, solder, and / or adhesive.

5. Joining the first end portion and the second end portion to each other includes: forming a contact region between the first end portion and the second end portion of the tire base layer; performing a welding operation to bond the first end portion and the second end portion within the contact region. The method according to any one of claims 1 to 4.

6. Joining the first length of tire base layer and the second length of tire base layer to each other includes forming a contact region between the first end portion and the second end portion of the tire base layer, and the method includes providing an adhesive within the contact region and applying pressure to the contact region. The method according to any one of claims 1 to 5.

7. Forming a contact region between the first end portion and the second end portion of the tire base layer includes placing the first end portion over the second end portion. The method according to any one of claims 5 or 6.

8. The first end portion is the first longitudinal plane of the tire base layer of the first length, the second end portion is the second longitudinal plane of the tire base layer of the second length, and forming a contact region between the first end portion and the second end portion includes abutting the first end portion against the second end portion. The method according to any one of claims 5 or 6.

9. The first longitudinal end and the second longitudinal end of the length of the tire base layer have complementary shapes, so that when the first end portion and the second end portion of the length of the tire base layer are abutted, a continuous tire base layer having parallel side surfaces is generated. The method according to claim 8.

10. The first longitudinal end and the second longitudinal end are formed as a single length perpendicular to the length of the tire base layer, each formed as a plurality of lengths perpendicular to the length of the tire base layer, formed non-perpendicular to the length of the tire base layer, or formed as a curve or a plurality of curves. The method according to claim 9.

11. The reinforcing element extends longitudinally from the first end portion and / or the second end portion of the tire base layer of the respective first length and the tire base layer of the second length such that the reinforcing element abuts and / or overlaps when the contact region is formed. The method according to any one of claims 5 to 10.

12. Joining the first end portion and the second end portion to each other includes arranging an insert between the longitudinal planes of the tire base layer of the first length and the tire base layer of the second length. The method according to claim 1, 2 or 3.

13. The insert includes a head portion that at least partially extends over the first end portion and the second end portion. The method according to claim 12.

14. The reinforcing element extends longitudinally from the first end portion and / or the second end portion of the tire base layer of the respective first length and the tire base layer of the second length such that the reinforcing element abuts and / or overlaps when the insert is arranged between the longitudinal plane of the tire base layer of the first length and the longitudinal plane of the tire base layer of the second length. The method according to claim 12 or 13.

15. The reinforcing element of the first pair of reinforcing elements can be joined to the corresponding reinforcing element of the second pair of reinforcing elements via a sleeve, a seam, welding, solder or glue. The method according to claim 14.

16. The method comprises: bonding a liner material to the tire base layer of the first length and the tire base layer of the second length so as to overlap the joint between the first end portion and the second end portion, the method according to any one of claims 1 to 15.

17. The liner material, the tire base layer of the first length and the tire base layer of the second length contain fibers, and the liner material is bonded to the tire base layer of the first length and the tire base layer of the second length such that the fibers of the liner material are aligned with the fibers of the tire base layer of the first length and the tire base layer of the second length, the method according to claim 16.

18. The liner material, when bonded to the tire base layer of the first length and the tire base layer of the second length, contains fibers such that the liner material contains fibers aligned in the longitudinal length of the tire base layer, the method according to claim 16 or 17.

19. The liner material is disposed on the lower surfaces of the first main portion and the second main portion, the method according to claim 16, 17 or 18.

20. The liner material continuously extends from the lower surfaces of the first main portion and the second main portion beyond the longitudinal edges of the length of the base layer to the upper surfaces of the base layer of the first length and the base layer of the second length, the method according to claim 19.

21. The liner material is disposed at a predetermined position on the joint before joining the first end portion and the second end portion, the method according to any one of claims 16 to 20.

22. Performing the method according to any one of claims 1 to 21 a sufficient number of times to create a circular loop of the tire base layer, the method according to any one of the claims.

23. The tire base layer of the first length and the tire base layer of the second length include a double-curved tire shape, and the double-curved tire shape has a radius r in the cross-section and a radius of curvature R in the cross-section perpendicular to the cross-section, the method according to any one of claims 1 to 22.

24. The method according to claim 23, wherein the method comprises: applying heat to the tire base layer and stretching the tire base layer on the surface of the wheel so that the tire base layer adopts a double-curved tire shape.

25. Providing a double-curved shape to each of the tire base layers of the first length and the second length includes providing a tire base layer of a length having a substantially flat shape, the substantially flat shape including at least one depression and at least one ridge, each depression and ridge extending and being inclined in both the lateral and longitudinal directions of the tire base layer, the method of claim 23. **Claim 26** The length of the tire base layer including the double-curved tire shape is providing a length of the tire base layer, inserting the length of the tire base layer into a cavity of a base mold, applying heat and pressure, and is manufactured by the base mold is a substantially flat mold comprising a housing with at least one longitudinal internal cavity extending between at least two opposing main walls and two opposing edge walls, each of the main walls has at least one ridge and at least one depression, each ridge and each depression extend and are inclined in both the lateral and longitudinal directions of the cavity, the ridges and the depressions are alternately arranged along the length of the mold, the ridges of one main wall face the depressions of the other main wall, the method of claim 25. **Claim 27** The length of the tire base layer including the double-curved tire shape is providing a length of the tire base layer, inserting the length of the tire base layer into a cavity of a base mold, applying heat and pressure, and is manufactured by the base shape of each of the tire base layers of the first length and the second length includes a segment of a cylindrical tire, the method of claim 23. **Claim 29** The method according to any one of claims 1 to 28, wherein the tire base layer of the first length and / or the second length includes a tread. **Claim 30** The tread is an overmolded tread, inserting the length of the tire base layer into a tread mold, injecting an elastomeric material into the tread mold, curing the elastomeric material such that the elastomeric material and the tire base layer adopt the shape of the tread mold, removing the bonded tire base layer and elastomeric material from the tread mold, and is provided by the method of claim 29. **Claim 31** The tread mold is a substantially flat tread mold comprising a housing having at least one longitudinal internal cavity extending between at least two opposing main walls and two opposing edge walls, each of the main walls having at least one ridge and at least one depression, each ridge and each depression extending and sloping in both the transverse and longitudinal directions of the cavity, the ridges and the depressions being alternately arranged along the length of the tread mold, the ridge of one main wall being opposite the depression of the other main wall, the method according to claim 30.

32. The tire base layer of the first length and / or the second length is provided according to claim 25, and the dimensions of the depressions and the ridges of the tire base layer are larger than the dimensions of the depressions and the ridges of the tread mold, the method according to claim 31.

33. The shape of the cavity of the tread mold includes at least one segment of a cylindrical tire, the method according to claim 30.

34. The tire base layer of the first length and the tire base layer of the second length are provided according to any one of claims 22 to 27, and the radius of curvature employed by the tire base layer of the first length and the tire base layer of the second length is larger than the radius of curvature of the cavity of the tread mold, the method according to claim 33.

36. The first end portion, the first main portion and the second main portion include a tread, the second end portion does not include a tread, and joining the first end portion and the second end portion includes joining the tread of the first end portion to the tread of the second main portion and / or joining the tread of the first end portion to the tire base layer of the second end portion, the method according to any one of claims 1 to 35 when dependent on claims 7 to 15.

37. The tread of the first end portion extends beyond the tire base layer of the first end portion in the longitudinal direction of the tire base layer, the method according to claim 36.

38. The tire base layer of the first length and the tire base layer of the second length each provide a sheet of material having a first side edge portion and a second side edge portion, the first side edge portion being separated from the second side edge portion by a central portion, placing a first reinforcing element on the sheet where the first side edge portion and the central portion intersect; placing a second bead wire on the sheet where the central portion and the second side edge portion intersect; folding the first side edge portion over the first reinforcing element; folding the second side edge portion over the second reinforcing element; fixing the first side edge portion and the second side edge portion to the central portion, the method according to any one of claims 1 to 37.

39. The method according to claim 38, wherein the first length base layer and / or the second length base layer is provided in the form of a continuous belt of a tire base layer.

40. A tire manufactured according to the method according to any one of claims 1 to 39.

41. An apparatus for joining a tire base layer of a first length and a tire base layer of a second length, the apparatus comprising a clamp for positioning a first end portion of the tire base layer of the first length and a second end portion of the tire base layer of the second length and performing a welding operation for joining the first end portion and the second end portion.

41. The apparatus according to claim 40, further comprising means for cutting a continuous belt of a tire base layer to a desired length for the tire base layer of the first length and / or the tire base layer of the second length.

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