KR20000012140A - A method of manufacturing a carcass structure for tyres, in particular for two-wheeled vehicles, and carcass structure obtainable thereby - Google Patents

Abstract

PURPOSE: A carcass structure for a two wheeled vehicle is provided to form an annular anchoring insert by an extending factor placing oppositely to the end flap of a strip-like section belonging to the first series. CONSTITUTION: The method for manufacturing the carcass structure for a tire comprises the steps of:preparing each strip shaped section(13,14) that contains a vertical and horizontal thread-like element(15) coated with a nature elastic material; and making at least one carcass ply(3) by placing the strip-like sections on a toroidal supporter(11) and distributing in a circumference direction. The strip-like sections define crown units(13b,14b) extending at two side parts(13a,14a) and at a radiation direction outside position between two side parts and the two side parts is placed in a shaft direction at a mutual interval and extended around the section outer line of the toroidal supporter.

Description

A method of manufacturing a carcass structure for a tire, particularly a two-wheeled vehicle, and a carcass structure obtainable thereby.

The present invention relates to a method of manufacturing a carcass structure for a tire, in particular a two-wheeled vehicle tire, comprising the steps of preparing a strip-shaped section each comprising a longitudinal tread-like element at least partially coated with at least one layer of natural elastic material; ;

The strip-shaped section on the toroidal support defines two sides extending in a U-shape and axially spaced apart around the cross section outline of the toroidal support, and a crown extending at a radially outward position between the two sides. Making at least one carcass ply by placing in and distributing in the circumferential direction;

-Attaching an annular reinforcement structure in a region proximate the inner circumferential edge of said at least one carcass ply.

The invention also relates to a carcass structure for a tire obtainable by the above-mentioned method, the carcass structure comprising: strip-shaped sections circumferentially distributed around a geometric axis of rotation, arranged longitudinally from each other; At least one carcass ply, each comprising at least two tread shaped elements at least partially coated of at least one layer of natural elastic material, wherein the individual strip shaped sections are substantially around a cross section outline of the carcass structure. To define two sides extending in a U-shape and spaced apart from each other in the axial direction, and crown portions extending at radially outward positions between the sides.

The completion of a tire for a vehicle wheel is substantially toroidal in shape, and has one or more axially opposite side edges that engage an annular reinforcement element that is not extendable in an individual circumferential direction, commonly referred to as a "bead ring." The formation of a carcass structure essentially made of a carcass ply.

At a circumferentially outer position, the belt structure is attached to the carcass structure, the belt structure being one or more belts in the form of a closed loop consisting essentially of a fabric or metal cord suitably steered relative to the cords belonging to each other and adjacent carcass plies. It includes a strip.

At present, a tread band consisting of a strip of elastic material of appropriate thickness is attached to the belt structure at a circumferential outer position therefrom.

For the purposes of this description, the term "elastic material" is intended to mean a complete rubber blend, ie it is at least one polymer suitably fused with reinforcing-fillers and / or various types of treatment additives. It can be pointed out that it means an assembly made of a polymer base.

Finally, a pair of sidewalls are attached to the opposite side of the tire being manufactured, each sidewall having a so-called shoulder region located proximate the corresponding side edge of the tread band and the corresponding bead ring. It covers the side part of the tire contained between what is called the bead located in.

According to a conventional production method, essentially the tire parts listed above are first separated from each other and then assembled during the tire manufacturing step.

Applicants have felt that these production methods have so far been at least partially unsatisfactory in terms of the quality of the finished product, and have problems with these production methods at the end of complex and difficult control processes.

Continuous fabrics or metals arranged longitudinally by extrusion and / or calendaring processes, for example, to make carcass ply (s) in combination with bead rings to form a carcass structure. It is desired to produce preferentially rubberized fabrics comprising cords. This rubber treated fabric is subjected to a transverse cutting operation to produce sections of predetermined size that are subsequently joined to give origin to continuous ribbon-like semi-finished products having parallel cords arranged transversely.

This article is then cut into sections whose length correlates with the circumferential extension of the carcass to be formed forward.

Instead of relying on the production of semi-finished products, a production method of making the carcass structure directly during the tire manufacturing stage has also been proposed.

For example, US Pat. Nos. 5, 362, 343 disclose methods and apparatus for forming carcass plies starting from a single cord that was previously wound around a reel.

According to the method and apparatus described in this patent, in the individual operating cycles of the device, it is pulled out of the reel by a power-driven idler-roller and held taut by a pneumatic tensioning system. The cord being cut is cut by size to get a section of predetermined length.

The cord section is lifted by a pick-up element mounted on a belt wound on a power driven pulley to extend transversely over the outer surface of the toroidal support.

The section distal end is then engaged by a slide element acting like a finger along the side of the cord section and by a belt-like bending member acting on the opposite side of the toroidal support to radially attach the cord section to the toroidal support. All.

The repetition of the operating cycle described above results in the attachment of a plurality of cord sections arranged side by side in the circumferential direction until the entire circumferential extension of the toroidal support is covered.

Not necessarily, the toroidal support has a dual function, that is, attached to the cord attached thereon to conveniently hold the cord in a fixed position, and to constitute an air-proof inner liner in the finished tire. The branches are precoated with a natural rubber layer.

The tire obtained by the production method is a carcass ply composed of individual cords arranged at intervals from each other in the axial direction and each having two sides facing in the radial direction of the rotation axis of the tire, and crown portions extending at radially outward positions between the sides. It has a carcass structure with (s).

Within the scope of carcass structure fabrication, the opposite ends of the individual cords forming the carcass ply near the individual tire beads form the bead ring, as can be seen in European Patent 0 664 231 and US Pat. Nos. 5,702, 548. Alternatingly arranged in axially opposite positions proportional to the annular fastening elements, the annular fastening elements have the form of crowns made of wire coils superimposed in a mutually radial direction. According to the disclosure of these patents, a filler of elastic material is necessarily inserted between the tread or wire forming the stationary annular insert and the carcass ply (s).

In French patent 384 231, referred to as an example of the most appropriate state of the art in this document, in the circumferential direction, a rectangle of rubberized fabric arranged side by side in a radial plane proportional to the geometric axis of the support drum itself The completion of a carcass structure is shown that includes attaching a series of small bands on a toroidal support. Attachment of the small band is performed in such a way that the end flaps of two discontinuous small bands are covered with the end flaps of the small band partially inserted therebetween. The space present between the end flaps covered with the small band is filled with a trapezoidal insert attached to the end flap of the small band at an overlapping position thereon. The attachment of the small bands is carried out in different overlapping layers, the number of which correlates to the thickness to be given to the carcass structure. The presence of the trapezoidal insert increases the hypertrophy of the carcass structure in the bead region such that the thickness in the bead ring is double the thickness in the crown.

U.S. Patent 4,248,287 describes the formation of a carcass structure, which comprises the steps of placing on a toroidal drum a plurality of layers each consisting of a rubberized wire and each formed of radial strips arranged circumferentially side by side. A method is disclosed. When the attachment is complete, the two bead rings are attached to the bead region, and the end flaps of the carcass layer formed from radial strips are folded about the rings.

Applicants are important in both aspects of simplifying the production process and improving tire behavioral characteristics if it is possible to conveniently create a strip-shaped section, each comprising a plurality of cords, which are combined into an elastomeric layer and parallel to each other, on a rigid toroidal support. It has been found that this can be achieved.

In this regard, Applicants have already developed several other manufacturing methods that are the subject of individual European patent applications.

For example, European patent applications Nos. 97830731.2 and 97830733.8 disclose manufacturing methods and tires in which the carcass structure is achieved by producing first and second carcass plies, respectively, obtained by strip-shaped sections placed side by side in mutual circumferential directions, respectively. do.

The tires obtained according to the contents described in the patent application are respectively disposed on opposite sides and have end portions of strip-shaped sections belonging to the first and second carcass plies, proportional to the annular reinforcement structure of the beads.

The expedient, in combination with the individual crossing directions of strip-shaped sections belonging to one and the other ply, provides a significant advantage in terms of the structural strength of the tire close to the beads and the sidewalls.

In European Patent Application No. 98830472.1, filed under the name of the same applicant, a section belonging to the first and second series is attached to the first and second strip-shaped section series at the end respectively on the opposite side proportional to the reinforcing structure of the beads. Completion of the carcass ply is shown.

Therefore, significant advantages can be achieved in terms of structural strength in tire beads and sidewalls even in the presence of a single carcass ply.

According to the present invention, the above-mentioned new manufacturing concept developed by the present applicant and all the advantageous aspects associated therewith, as well as motorcycles and the like, provided that a particular construction method is adopted to make the reinforcing structure in the beads It has been found that it can be advantageously used in the tire manufacturing field.

More specifically, Applicants believe that the construction methodology they have developed satisfactory quality of structural strength in the beads, even when using a reinforcing structure comprising a single annular insert formed from at least one elongate element wound on a radially overlapping coil I found it surprisingly possible to get it. Applicants also find that carcass structures having such annular reinforcement structures in beads are particularly suitable for the manufacture of motorcycle tires using manufacturing methods that provide for the completion of carcass plies by strip-shaped section attachment on rigid toroidal supports. I also found out that it is suitable.

More particularly, the present invention relates to a method of manufacturing a carcass structure for a car tire, wherein the completion of the individual annular reinforcement structure comprises: placing at least one elongate element in the concentric coil so as to form a generally crowned annular fastening insert; And forming at least one filler of natural elastic material, and connecting the filler to the annular fastening insert.

In a preferred embodiment, the completion of the carcass ply comprises: placing a first series of the strip-shaped sections circumferentially distributed on the toroidal support at a circumferential pitch corresponding to a multiple of the strip-shaped section width;

Attaching the annular reinforcing structure to the distal flap of the strip-shaped section belonging to the first series;

On the toroidal support, each of which extends in a U-shape around a cross-section outside of the toroidal support to define the carcass ply between two consecutive sections of the first series, and is axially opposite in proportion to the end of the first series section. And disposing at least one second series of said strip-shaped sections on said toroidal support having end flaps that overlap each annular reinforcement structure in position.

It is also preferably suggested that the crown portions of the strip-shaped section should be arranged side by side along the circumferential extension of the toroidal support.

The sides of the individual strip-shaped sections 13 belonging to the first series are at least one belonging to the second series in an extension line included between the radially outer edge of the annular reinforcement structure and the transition region between the sides and the crown portion. It can also be presented that it is partially covered by the side of the circumferential continuous section of.

In more detail, the covering of the individual strip-shaped section sides belonging to the first series gradually starts from the maximum near the outer circumferential edge of the individual annular reinforcement structure and gradually reaches the zero value of the transition region of the side and crown portions. Decreases.

Preferably, the sides of the strip-shaped section are concentrated radially in the direction of the geometric axis of rotation of the toroidal support.

At least one operating step that defines an increased width region proximate the inner circumferential edge of the carcass structure may also be presented.

As presented in an alternative embodiment, the preparation of the strip shaped section is caused by a cutting action, which is in turn performed on at least one continuous strip shaped element that couples the tread shaped element to the layer of natural elastic material, The defining step of the increased width region can advantageously be carried out on the continuous strip shaped element before the execution of the cutting action.

According to a further aspect of the invention, the elongate element is preferably arranged directly against the carcass ply, more particularly against the end flap of the strip shaped section belonging to the first series, so that the strip shaped section itself Form an annular locking insert in direct contact with the.

Preferably the filler at a radially outward position proportional to the annular fastening insert is provided by laying a continuous strip of natural elastic material against the annular insert itself which is pre-attached to the end flap of the strip-shaped section belonging to the first series. Can be formed.

It is a pair of annular reinforcement structures engaged in a proximal region of the respective inner circumferential edge of the carcass ply and, respectively: coaxially disposed with the carcass structure, adjacent to the inner circumferential edge of the carcass ply and in the form of an alternate crown. An annular locking insert formed of at least one elongate element extending from the concentric coil;

A further object of the invention is a carcass structure of a vehicle wheel, characterized in that it further comprises a filler of natural elastic material bonded to said annular fastening insert.

More specifically, the carcass ply is presented to include a series of first and second strip shaped sections preferably arranged in an intersecting order along the circumferential extension of the carcass structure, each annular reinforcing structure being It has an axial inward curled towards the end flap of the section belonging to the first series and an axial outward curled towards the end flap of the section belonging to the second series.

Preferably, the crown parts belonging to the sections of the first and second series respectively are arranged next to each other along the circumferential extension of the carcass structure.

The sides of each strip-shaped section belonging to the first series are each at least one adjacent belonging to the second series in an extension included between the radially outer edge of the annular reinforcement structure and the transition region between the side and the crown portion. It can be shown that it is covered with the strip shaped section side.

More specifically, the covering of the individual strip-shaped section sides belonging to the first series starts from the maximum near the outer circumferential edge of the individual annular reinforcement structure and reaches zero value of the transition region between the side and the crown portion. Gradually decreases.

Advantageously, the sides of the strip-shaped section are focused radially in the direction of the geometric axis of rotation of the carcass structure.

The individual strip-shaped sections belonging to one of the first or second series are each preferably arranged at a circumferential distribution pitch corresponding to a multiple of the width of the strip-shaped section itself.

Each strip-shaped section may have an increased width region in the region near the inner circumferential edge of the carcass structure.

In this case, the tread shaped elements contained in the individual strip shaped sections are arranged at mutually spaced apart in said increased width region.

Preferably, each said strip shaped section has a width comprised between 3 mm and 15 mm and has between three and eight tread shaped elements.

In particular, the tread-shaped raw material is placed in each strip-shaped section according to the intercenter distances greater than 1.5 times its own diameter.

According to a further aspect of the invention, the annular fastening insert has a single series of concentric coils radially superimposed.

In addition, the filler preferably extends radially in the annular fastening insert, from which it must taper off.

More specifically, the annular locking insert and the radial extension ratio of the filler can advantageously be included between 0.5 and 2.5.

For convenience, the filler of natural elastic material has a hardness included in Shore D between 48 ° and 55 ° at 23 ° C.

Further details and advantages will be clarified by the detailed description of the preferred and general embodiments of the carcass structure for the tire according to the invention, in particular for two-wheeled vehicle tires, and the carcass structure obtainable with the method. Statements relating to the accompanying drawings, which are presented as non-limiting examples, are set forth below, in the drawings:

1 is a partially exploded perspective view of a tire with a carcass structure made in accordance with the present invention;

2 shows a row of continuous strip shaped elements intended to form carcass ply (s);

3 is a cross-sectional view of an embodiment of the strip shaped element;

4 is a partial perspective view schematically showing a deposition sequence of a series of first strip-shaped sections for carcass ply formation of a tire according to the present invention;

5 is a partial perspective view of an annular reinforcing structure attached side to the end flap of the strip-shaped section belonging to the first series;

FIG. 6 is a partial perspective view schematically illustrating the attaching sequence of strip-shaped sections of a second series with individual end flaps overlapping the annular reinforcement structure. FIG.

Referring to the drawings, tires with a carcass structure 2 according to the invention, in particular tires of two-wheeled vehicles, are generally designated with reference numeral 1.

The carcass structure 2 is substantially toroidal in shape and has at least one carcass ply engaged with a pair of annular reinforcement structures 4 (only one of which is shown in the figure) by its opposite circumferential edge. 4), a pair of annular reinforcement structures are each located in the area usually designated "beads" at the end of tire manufacture.

In the circumferentially external position, the belt structure 5 is attached to the carcass structure 2, which is formed by one or more continuous cords wound around coils arranged substantially parallel to and axially parallel to the circumferential extension of the tire. And a secondary belt strip 6a, 6b at radially inner positions proportional to the primary belt strip 7 formed. Following the molding operation carried out concurrently with the tire vulcanization, the tread in which longitudinal and / or transverse grooves 8a are formed which are arranged to define the desired "tread pattern" The band 8 is superimposed on the belt structure 5 in the circumferential direction.

The tire also includes a pair of so-called "side walls" 9 laterally attached to the carcass structure 2 on the opposite side of the carcass structure 2.

The carcass structure 2 consists of an air-resistant layer 10 on the inner wall, ie essentially an air impermeable elastic material layer, so-called "liners" suitable for ensuring a hermetic seal of the inflated tire. Coated with.

The assembling of the components listed above, as well as the production of one or more identical products, takes place with the aid of the toroidal support 11, a toroidal support having the form of the inner wall of the tire to be produced, shown schematically in FIG. 1.

The toroidal support 11 comprises a finished tire with a linear amount, preferably between 2% and 5%, measured as one indication, along the circumferential extension of the support itself in the equator plane XX, which coincides with the equator plane of the tire itself. It can have a reduced size when compared.

The toroidal support 11 has not been described or depicted in detail as it is not particularly important for the purposes of the present invention, and for example in an expanded state by being composed of a suitably reinforced shrinking drum or inflatable bladder. The desired toroidal shape can be taken and maintained.

After the above statement, the manufacture of the tire 1 first comprises the formation of a carcass structure 2 which starts with the possible formation of the liner 10.

The liner 10 toroidals at least one ribbon-shaped small band 12 of air-resistant natural elastic material produced from an extruder and / or calender positioned proximate to the toroidal support 11 itself. It can be preferably made by winding in the circumferential direction around the support 11. As can be seen in FIG. 1, the ribbon-shaped small band 12 winding substantially occurs in circumferential coils arranged side by side along the outer surface cross-sectional outline of the toroidal support 11.

For illustrative purposes, "cross-section outside" is intended herein to be a form revealed by a half-section of the toroidal support 11 partitioned along the radial plane of the geometric axis of rotation, where the geometric axis of rotation Is not shown in the figure and corresponds to the geometric axis of rotation of the tire, so that a carcass structure 2 is produced.

According to the invention, the carcass ply 3 is first and second series drawn from at least one continuous strip shaped section 13 preferably having a width comprised between 3 mm and 15 mm, as will become more apparent later. By arranging the strip shaped sections 13, 14 of the substrate, it is formed directly on the toroidal support 11.

As can be seen in FIG. 2, the preparation of the continuous strip-shaped element 2a comprises at least one tread-shaped element 15 and preferably three to ten tread-shaped elements (supplyed from the individual reels 15a). It is essentially suggested that 15) should be guided through the extruder 16 associated with the extrusion device 17 which carries out the natural elastic material feed through the extruder itself.

In this description, the term "extruder" refers to the portion of the extrusion apparatus that is designated in this particular field as the term "extrusion head", in which the shape and size are specified in accordance with the geometric and dimensional features imparted to the product itself. It is pointed out that the so-called "die" passed by the product worked at the outlet being provided is provided.

The elastic material and tread shaped element 15 are tightly coupled within the extruder 16, thereby generating a continuous strip shaped element 2a at its outlet, where the strip shaped element itself is joined to the tread shaped element itself. It is formed of at least one layer of elastic material 18 having a thickness.

Depending on the requirements, the tread shaped element 15 may be guided in the extruder 16 in such a way that it appears on one or both surfaces of the layer rather than being integrally bonded to the layer of elastic material 18.

The tread shaped element 15 may for example consist of a fabric cord having a diameter comprised between 0.6 and 1.2 mm, or a metal cord having a diameter comprised between 0.3 and 2.1 mm.

Preferably, the tread shaped element 15 can be arranged in the continuous strip shaped element in a manner that provides the carcass ply obtained with an unexpected quality of compressibility and homogeneity, if necessary. For this purpose, the tread shaped element 15 is measured in the circumferential direction, for example on a carcass ply 2 proximate to the equator plane of the tire 1, arranged according to a thickness greater than six tread shaped elements / cm. Can be. In some cases, the tread shaped element 15 should be placed on the strip shaped element 2a at a mutual distance between the centers greater than 1.5 times the diameter of the tread shaped element itself to enable proper rubber handling operation between adjacent treads. Is preferably presented.

The continuous strip shaped element 2a exiting the extruder 16 can be preferably guided onto the attachment device, optionally via an accumulator-compensator 19, the structural and operating characteristics of which are the same. It is described in more detail in European Patent Application No. 97830731.2 filed in the name of the Applicant and is hereby incorporated by reference.

This attachment device is suitable for sequentially cutting the continuous strip shaped element 2a into strip shaped sections 13, 14 of a predetermined length.

After cutting of the individual strip-shaped sections 13, 14, the attachment of the strip-shaped section immediately upon the toroidal support 11 is followed by providing a U-shaped configuration in the strip-shaped section around the cross-sectional outline of the toroidal support itself. Thus, in the strip-shaped sections 13, 14 two sides 13a, 14a can be designated, in which the two sides are radially directed towards the axis of the toroidal support 11 at positions arranged spaced apart from one another in the radial direction. Crowns 13b, 14b, which extend in the radial direction and between radially outer positions between the two sides themselves, may also be designated.

The sticky character of the natural elastic material forming layer 18 coating the tread shaped element 15 is characterized by a strip-shaped section 13, which is formed on the surface of the toroidal support 11 even in the absence of the liner 10 on the toroidal support itself. Ensure a stable adhesion of 14). More specifically, the above described adhesion takes place as soon as the strip shaped sections 13, 14 contact the toroidal support 11 in the radially outer region of the toroidal support cross section outline.

In addition to or in place of the development of the natural tack of the elastic material described above, the retention of one or more strip-shaped sections 13, 14 on the toroidal support may include one or more suitable holes arranged on the toroidal support itself. It can be obtained by performing the suction action generated through.

The toroidal support 11 is followed by the attachment of the strip-shaped section to a position circumferentially spaced from the pre-placed sections 13, 14 after the individual cutting action of the individual strip-shaped sections 13, 14. In a following manner it can be driven in angular rotation with a stepwise movement in synchronization with the operation of the attachment device.

More specifically, the rotation of the toroidal support 11 takes place in an angular pitch where the circumferential displacement is a multiple of the width of the individual strip-shaped sections 13, 14, more specifically twice.

For the purposes of the present invention, it is pointed out that the term "circumferential", unless stated otherwise, refers to the circumference which lies in the equator plane and is close to the outer surface of the toroidal support 11.

According to the invention, the above-described operating sequence results in the first series attachment of the strip-shaped section 13 by means of a first full rotation about its own axis of the toroidal support 11, wherein the section 13 is a separate section. This occurs in a manner that is distributed in the circumferential pitch corresponding to twice the width. Therefore, as can be clearly seen in FIG. 4, an empty space “S” remains between sections belonging to the first series, which is at least equal to the width of the section itself in the crown portion 13b of the section. Has

According to the requirements, the attachment of the strip-shaped section 13 belonging to the first series is carried out in the radial plane of the axis of rotation of the toroidal support 11, as described in European Patent Application No. 98830778.1 filed in the name of the same applicant; This can occur in an offset plane parallel to the radial plane.

In addition, this attachment can be carried out along an inclined orientation proportional to the circumferentially extending direction of the toroidal support 11, for example, at an angle comprised between 3 and 15 degrees.

The attachment angle adjustment of the strip-shaped section can be obtained, for example, by orienting the geometric axis of rotation of the drum proportionally with the attachment device.

The completion of the carcass structure 2 is then carried out in particular with the annular reinforcement structure mentioned above, in order to secure a carcass area known as "beads", intended to fix the tire to the corresponding mounting rim. 4) is then attached to the area proximate each of the circumferential edges inside the carcass ply 3 to be manufactured.

The individual annular reinforcement structure 4 preferably comprises individual annular fastening inserts 21 which cannot extend substantially in the circumferential direction and have a concentric crown shape with the geometric axis of rotation of the toroidal support 11, The insert is in a circumferentially inner position against the distal flap of the strip-shaped section 13 belonging to the first series.

The annular fastening insert 21 is made of at least one elongated metal element wound on several substantially concentric concentric coils 21a. The coil 21a may be defined by a continuous threaded coil or concentric rings formed from individual elongate elements.

Preferably, the filler body 22 is at a radially outer position proportional to the annular fastening insert 21. More specifically, the filler body 22 is connected to the annular fastening insert 21 and extends in the radial direction, and has a taper radially inner edge therefrom. Preferably, the ratio between the radial insert 21 and the radial extension of the filler body 22 is comprised between 0.5 and 2.5.

For the purposes of the present invention, "radially extending" means between the maximum and minimum radii measured at the radially outer edge and the inner edge of the filler body 22 and / or the annular fastening insert 21, respectively. Intended the difference.

According to a preferred embodiment, the annular fastening insert 21 is produced directly against the end of the strip-shaped section 13, through the formation of the coil 21a by the winding of the elongate element, optionally with the toroidal support 11. With the aid of a roller or other suitable device acting against the surface.

The adhesiveness of the elastomer layer 18 coating the strip-shaped section 13 belonging to the first series, including the optional liner 10 pre-positioned on the drum itself, ensures stable positioning of the individual coils 21a during the forming step. To ensure.

The rubber treatment step in which the stretching element itself is coated with at least one layer of natural elastic material which not only ensures good rubber-metal bonding on the stretching element but also promotes adhesion of the same may preferably be carried out before the attaching step of the stretching element. have.

Filler 22 may then be formed in direct contact with annular securing insert 21, for example by attaching a strip of continuous elastic material exiting the extruder located proximate to the drum. The continuous strip may already have a definite shape in the filler 22 section as soon as it exits the individual extruder. Alternatively, the continuous strip has a reduced section proportional to the section of the filler, the filler section being obtained by attaching the strips in several coils arranged side by side and / or in an overlapping relationship to the We will define the final configuration.

After attachment of the annular reinforcing structure 4, the formation of the carcass ply 3 is obtained by cutting the continuous strip shaped element 2a by size and as described for the strip shaped section 13 belonging to the first series. In the same way it is completed by the attachment of the second series of strip-shaped sections 14 attached to the toroidal drum 11.

As can be clearly seen in FIG. 6, each section 14 belonging to the second series has a cross-sectional outline of the toroidal support 11 in an orientation parallel to the two sections between two successive sections 13 belonging to the first series. It is arranged in a U shape at the center. More specifically, each section 14 belonging to the second series is located between the crown portions 13a of the section belonging to the first series at an axially opposite position proportional to the distal flap of the section 13 belonging to the first series. Each crown portion 14b inserted circumferentially into the space "S" therebetween, and a pair of sides carrying the end flaps of the section itself in an overlapping state with each annular reinforcement structure 4 ( 14a).

That is, each annular reinforcement structure 4 of the tapered outline that is tapered from the tire axis is axially inwardly rolled toward the end flap of the strip-shaped section 13 belonging to the first series and the section belonging to the second series ( 14) It has an axial outward curled towards the end flap.

The side portion 14a of each section 14 belonging to the second series is comprised between the radially outer edge of each annular reinforcing structure 4 and the transition region between the side itself and the crown portions 13b and 14b. It can also be suggested that in the expanded part, it must partially cover the side 13a of the two consecutive sections 13 belonging to the first series.

Due to the mutual convergence between adjacent sides 13a, 14a facing radially in the geometric axis of the toroidal support 11, overlapping or covering, ie overlapping, of the sides 13a of the section 13 belonging to the first series The circumferential width of the region starts at the maximum value close to the radially outer edge of the first portion 4a of each annular reinforcement structure 4, so that the side portions 13a, 14a and the crown portions 13b, 14b. It gradually decreases until it becomes 0 in the transition region between.

If a more even distribution of the tread-shaped elements 15 forming sections 13 and 14 of the first and second series, respectively, should be expected near the beads, the pressing step is carried out by strip-shaped sections 13 and 14 obtained by cutting. It can be carried out on the continuous strip-shaped element 2a in the longitudinally extending region of the strip-shaped section corresponding to the end of the). In this way, an increased width region located proximate the inner circumferential edge of the formed carcass ply 3 is defined on the extension of each strip-shaped section 13, 14.

The compacting action results in a decrease in the thickness of the elastic layer 18 and an increase in the width of the strip shaped element 2a, with the result that the tread shaped elements 15 are arranged at a spaced interval from each other. The end flaps of each section 13, 14 are thus exactly twice the width of the crown portions 13b, 14b at the circumferential inner ends and in all cases completely cover the inside and outside of each annular reinforcement structure 4. It can be widened until it reaches the width it can.

In radial tires, the belt structure 5 is usually attached to the carcass structure 2.

This belt structure 5 can be made in a manner convenient to a person skilled in the art, for example a main belt obtained by winding at least one continuous cord in coils axially arranged side by side on a carcass ply 3. It essentially comprises a strip 7. At the same time as the main strip 7, a reinforcement layer may be further provided. The reinforcement layer is conveniently made of a strip of fabric and / or felt material, ie a mixed layer of short reinforcement fibers of, for example, synthetic polyamide type.

In the example shown the belt structure further comprises first and second auxiliary belt strips 6a, 6b, each having a cord in the cross direction and disposed in radially inner positions proportional to the main strip 7.

Then, the tread band 8 and the side wall 9 are attached to the belt structure 5, which can be obtained by a person skilled in the art in a convenient manner.

The tire 1 thus produced can be entered into a vulcanization step, which can be carried out in a known conventional manner after being removed from the support 11.

The present invention achieves the following important advantages.

The carcass structure of the present invention can in fact be obtained directly on a toroidal support on which the entire tire can be preferably formed. In this way, all problems associated with the management of manufacturing, storage and semi-finished products which are usually present in conventional manufacturing processes are eliminated.

Compared to the method described in US Pat. No. 5,362,343, the manufacturing time for each carcass ply is characterized by the fact that a number of tread shaped elements are formed by the continuous strip shaped elements (13, 14) or the sections 13, 14 from which Due to the simultaneous attachment of the tread shaped elements as contained in 2a), they can be greatly reduced. The use of the strip shaped sections 13, 14 also eliminates the need to pre-attach the liner 10 on the toroidal support 11. In fact, the elastomeric layer 18 used in forming the continuous strip shaped element 2a can, by itself, ensure effective attachment of the element 2a to the toroidal support 11, thereby allowing individual sections ( 13, 14) to ensure stable positioning.

The accuracy in determining the position of the strip-shaped elements 13, 14 and the tread-shaped elements formed integrally therein is such that each strip-shaped section can be vibrated or similar oscillation that can be transmitted from the attachment device. This can be further improved by the fact that it has a large structural consistency that makes it unresponsive to the effect.

In this regard, as described in US Pat. No. 5,362,343, the attachment of individual cords can be somewhat problematic due to the vibrations and / or oscillations generated by the cords, strictly during the attachment step.

Moreover, the simultaneous attachment of multiple tread shaped elements according to the invention allows the attachment device to be operated at a speed lower than the speed required for the attachment of the individual cords, which on the one hand is more in terms of work accuracy without loss of productivity. It is a further advantage.

In addition, the crown-shaped attachment of strip-shaped sections directly to a toroidal support of an outline substantially the same as the outline of the finished tire allows to achieve a thickness that is unreachable by methods known in the art. The resultant thinning of the carcass ply cord arranged crowned on the tires provides the attachment of the carcass ply in the form of a cylindrical sleeve and the toroidal shape of the carcass ply thereafter.

In addition to the above, the individual strip-shaped sections can be reliably fixed to the toroidal support by means of a vacuum effect generated through possible suction ducts, where the vacuum stable attachment is known to effect individual cord attachment. It cannot be achieved by the treatment process.

If desired, the sides of the strip-shaped section can be arranged at a moderately increased slope proportional to the radial direction of the toroidal support axis, which effectively aids in the expansion caused by the tire during the stretching step applied to the tire in vulcanization. To receive it. Under these circumstances, in fact, the sides 13a, 14a tend to orient radially in the tire by the expansion effect applied to the tire.

The construction and structure concept of the present tires, in particular with respect to the carcass structure 2 of the tire, in terms of structural strength, in particular in terms of structural strength and road surface conditions close to the sidewalls and beads where higher structural strength is usually required. It achieves a significant improvement while at the same time benefiting from a single fly carcass structure and all of the benefits normally associated with it.

In particular, the structural features of the non-extensible annular structure 4 and, thus, the modality with which these structures are coupled to the carcass ply 3, are adapted to provide the best structural strength to the tire 1. At the same time, the tire thickness at the beads is greatly limited in accordance with the typical requirements of motorcycle tires.

In fact, the coil 21a is tightly coupled to the carcass ply 3 and the circumferentially non-extensible ring which is substantially perpendicular to the tread shaped element 15 belonging to another series of strip shaped sections 13, 14. The presence of the shape insert 21 provides the best engagement with the tread shape element itself. The carcass structure 2 is thus wound like a slipknot on the annular reinforcement structure 4 and corresponds to the tire bead without requiring the use of additional strip shaped inserts, commonly referred to as "flippers". In contrast, the use of additional strip shaped inserts is made in the prior art.

Claims (29)

In a method of manufacturing a carcass structure for a tire, in particular a two-wheeled vehicle Preparing strip-shaped sections 13, 14 each comprising a transverse tread-shaped element 15 at least partially coated with at least one layer of natural elastic material; Two sides 13a, 14a, which extend in a U-shape around the cross-sectional outline of the toroidal support 11 and are spaced apart from each other in the axial direction, and extend in a radially outer position between the two sides 13a, 14a; Making the at least one carcass ply 3 by disposing the strip-shaped sections 13, 14 defining the crown portions 13b, 14b to be distributed on the toroidal support 11 in the circumferential direction; ; -Attaching the annular reinforcement structure 4 to a region proximate the inner circumferential edge of the at least one carcass ply 3, Completion of each annular reinforcement structure 4 is: Placing at least one elongate element in the concentric coil 21a to form an annular fastening insert 21 substantially in the form of a crown; Forming at least one filler body 22 of natural elastic material; -The method of manufacturing a carcass structure for a tire, characterized in that it comprises the step of connecting the filler (22) to the ring-shaped fixing insert (21). The method of claim 1, wherein the completion of the carcass ply (3) is: Placing on said toroidal support (11) a first series of said strip-shaped sections (13) distributed circumferentially at a circumferential pitch corresponding to a multiple of the strip-shaped sections (13, 14) width; Attaching the annular reinforcing structure (4) to the end flap of the strip-shaped section (13) belonging to the first series; Above the toroidal support 11, each extending in a U-shape around a cross-section outside of the toroidal support 11 to define the carcass ply 3 between two consecutive sections of the first series 13 and At least one second series of strip-like sections 14 having end flaps overlapping each annular reinforcement structure 4 at axially opposite positions proportional to the ends of the first series sections 13. Method of producing a carcass structure for a tire, characterized in that comprises a step of placing on the support 11 this month. The method of claim 2, The crown portion (13b, 14b) of the strip-shaped section (13, 14) is a carcass structure manufacturing method for a tire, characterized in that arranged continuously side by side along the circumferential extension of the toroidal support (11). The method of claim 3, The sides 13a of the individual strip-shaped sections 13 belonging to the first series are provided between the radially outer edges of the annular reinforcement structure 4 and between the sides 13a, 14a and the crowns 13b, 14b. A method of manufacturing a carcass structure for a tire, characterized in that it is partially covered by the side portions (14a) of at least one circumferential continuous section (14) belonging to the second series in an extension line included between the transition regions. The method of claim 4, wherein The covering of the individual strip-shaped section 13 sides 13a belonging to the first series starts from the maximum near the outer circumferential edge of the individual annular reinforcement structure 4, so that the sides 13a, 14a and the crown A method for producing a carcass structure for a tire, characterized by gradually decreasing until the zero value of the transition region of the section (13b, 14b) is reached. The method of claim 1, The side (13a, 14a) of the strip-shaped section (13, 14) is concentrated radially in the direction of the geometric axis of rotation of the toroidal support (11). The method of claim 1, A method for producing a carcass structure for a tire, characterized by further comprising defining an increased width region proximate the inner circumferential edge of the carcass structure (2). The method of claim 7, wherein The preparation of the strip-shaped sections 13, 14 is in turn a cutting action performed on at least one continuous strip-shaped element 2a that couples the tread-shaped element 15 to the layer of natural elastic material 18. And the step of defining the increased width region is carried out on a continuous strip-shaped element (2a) prior to the execution of the cutting action. The method of claim 1, Method for producing a carcass structure for a tire, characterized in that the elongate element is placed in direct contact with the carcass ply (3). The method of claim 2, The elongate element is arranged directly against the end flap of the strip-shaped section 13 belonging to the first series and forms an annular fastening insert 21 which is in direct contact with the strip-shaped section itself. Structure manufacturing method. The method of claim 1, Method for producing a carcass structure for a tire, characterized in that the filler body (22) is in a radially outward position proportional to the annular fastening insert (21). The method of claim 1, The filler body 22 is formed by placing a continuous strip of elastic material directly on a pre-arranged annular insert 21, so that the connecting step is carried out simultaneously with the formation of the filler body 22. Curse structure manufacturing method. In carcass structures for tires, especially two-wheeled tires: At least two tread-shaped elements comprising strip-shaped sections 13, 14 distributed circumferentially about a geometric axis of rotation, positioned laterally from one another and at least partially coated with at least one layer of natural elastic material 18 ( At least one carcass ply (3) each comprising 15), wherein said strip shaped sections (13, 14) extend in a generally U-shape around a cross-sectional outline of the carcass structure in an axial direction, respectively. A carcass ply (3) characterized by defining two sides (13a, 14a) spaced from each other and crowns (13b, 14b) extending at radially outward positions between the sides; It further comprises a pair of annular reinforcement structures 4 coupled in the proximal region of each inner circumferential edge of the carcass ply 3, each of which is: An annular shape arranged coaxially with the carcass structure 2 and adjacent to the inner circumferential edge of the carcass ply 3, generally in the form of a crown, formed of at least one elongate element extending from the concentric coil 21a. Fixed insert 21; And A method of manufacturing a carcass structure for a tire, characterized in that it comprises a filler (22) of a natural elastic material bonded to the annular fastening insert (21). The method of claim 13, The carcass ply (3) is: A series of first and second strip-shaped sections 13, 14 arranged in a crossover order along the circumferential extension of the carcass structure 2, and Each said annular reinforcement structure having an axial inward curled towards the end flap of the section 13 belonging to the first series and an axial outward curled towards the end flap of the section 14 belonging to the second series Carcass structure for tires, characterized in that comprises (4). The method of claim 14, The carcass structure for a tire, characterized in that the crown portions (13b, 14b) belonging to the sections (13, 14) of the first and second series are arranged next to each other along the circumferential extension of the carcass structure (2), respectively. The method of claim 15, The side portion 13a of each strip-shaped section belonging to the first series is between the radially outer edge of the annular reinforcement structure 4 and the transition region between the side portions 13a and 14a and the crown portions 13b and 14b. Carcass structure for a tire, characterized in that it is partially covered with sides (14a) of at least one adjacent strip-shaped section (14) belonging to the second series in an extension included in the second series. The method of claim 16, The covering of each strip-shaped section 13 side 13a belonging to the first series starts from the maximum near the outer circumferential edge of the individual annular reinforcement structure 4, so that the sides 13a, 14a and the crown Carcass structure for a tire, characterized in that it gradually decreases until the zero value of the transition region between the portions (13b, 14b) is reached. The method of claim 13, The side (13a, 14a) of the strip-shaped section (13, 14) is characterized in that the carcass structure for the tire is concentrated in the radial direction in the direction of the geometric axis of rotation (2). The method of claim 14, The carcass of the tire, characterized in that the individual strip-shaped sections 13, 14 belonging to one of the first or second series are preferably arranged at circumferential distribution pitches corresponding to multiples of the width of the strip-shaped section itself. rescue. The method of claim 13, A carcass structure for a tire, characterized in that each strip-shaped section (13, 14) has an increased width region in an area proximate the inner circumferential edge of the carcass structure (2). The method of claim 13, Carcass structure according to claim 1, characterized in that the tread-shaped elements (15) contained in each strip-shaped section (13, 14) are spaced apart from each other in the increased width region. The method of claim 13, Carcass structure for a tire, characterized in that the individual strip-shaped sections (13, 14) have a width comprised between 3 mm and 15 mm. The method of claim 13, Carcass structure for a tire, characterized in that each of said strip shaped sections (13, 14) comprises three to eight tread shaped elements (15). The method of claim 13, The tread shaped element (15) is characterized in that it is arranged in each strip-shaped section (13, 14) according to the mutual distance between the centers greater than 1.5 times its own diameter. The method of claim 13, Said annular fastening insert (21) has a single series of concentric coils radially overlapping. The method of claim 13, The filling body (22) extends in the radial direction from the ring-shaped fixing insert (21), tapering from there. The method of claim 13, Carcass structure for a tire, characterized in that the radial extension ratio of the annular fixing insert (21) and the filler (22) is comprised between 0.5 and 2.5. The method of claim 13, The filler body 22 made of an elastic material has a hardness included in Shore D between 48 ° and 55 ° at 23 ° C. Carcass structure for tires. Tires having a carcass structure made according to one or more preceding claims, in particular tires for two-wheeled vehicles.