Truck tire

Abstract

The invention relates to a truck tire. A tire includes a tread, two working belts, and an intermediate belt disposed radially between the two working belts. In addition, the tire further comprises a top belt layer comprising reinforcing cords having an impact energy absorption rate higher than 7 J / mm2. In one aspect, the intermediate belt includes a first layer extending over at least 70% of an axial maximum working belt axial width, and one or more further layers underlying one or more shoulder grooves extending over at most 50% of the axial width. In another aspect, the intermediate belt layer comprises a metal cord having the structure a + b x d, where a is 1 to 5, b is 2 to 7, and d is 0.2 mm to 0.5 mm. In another aspect, the intermediate belt has a rubber permeability of at least 90% along at least 90% of its axial width.

Description

TECHNICAL FIELD

[0001] The present invention relates to a tire comprising a belt portion comprising a middle belt and a top belt. In particular, the tire can be a pneumatic tire, such as a truck pneumatic tire. BACKGROUND

[0002] Modern pneumatic truck tires should meet a number of different performance requirements, such as low rolling resistance and / or high wear resistance. It is also desirable that such tires are robust and durable. In particular, forces in the groove and / or shoulder region of the tire should be reduced. For example, these forces can be reduced by employing advanced tread structures. Although progress has been made in the development of robust and durable tires, such as robust and durable truck tires, over the past decades, there is still room for improvement. SUMMARY

[0003] In a first aspect of the invention, the invention relates to a tire comprising a tread and a belt portion located radially below the tread. The tread has two shoulder portions, wherein each shoulder portion comprises a shoulder groove, wherein the belt portion comprises a pair of working belts and a middle belt, and wherein the pair of working belts comprises a first working belt and a second working belt arranged radially above the first working belt. The middle belt is arranged between the first working belt and the second working belt and has elongated reinforcing elements having an angle with the circumferential direction of the tire of less than 5°, wherein the middle belt further comprises a first layer and one or more further layers. The first layer of the middle belt extends over at least 70% of the axial width of the axially largest working belt of the pair of working belts, wherein each of the one or more further layers of the middle belt is arranged radially below one of the shoulder grooves and extends over at most 50% of the axial width of the axially largest working belt. Further, the belt portion comprises a top belt arranged radially above the second working belt and comprising reinforcing cords having an impact energy absorption higher than 7 J / mm 2

[0004] ​In a second aspect of the application, the application relates to a tire comprising a tread and a belt portion located radially below the tread, wherein the tread has two shoulder portions each comprising a shoulder groove, and wherein the belt portion comprises a pair of working belts and a middle belt. Further, the pair of working belts comprises a first working belt and a second working belt located radially above the first working belt, the middle belt being disposed between the first working belt and the second working belt and comprising metal cords having the following characteristics: i) an angle with the tire circumferential direction of less than 5°, ii) a cord structure according to a + b x d, with a ranging from 1 to 5, b ranging from 2 to 7, and d ranging from 0.2 mm to 0.5 mm. Further, the belt portion comprises a top belt disposed radially above the second working belt, wherein the top belt comprises cords having an impact energy absorption greater than 7 Joule per square millimeter (J / mm 2 ).

[0005] In a third aspect of the application, the application relates to a tire comprising a tread and a belt portion located radially below the tread, wherein the tread has two shoulder portions each comprising a shoulder groove, and wherein the belt portion comprises a pair of working belts and a middle belt. Further, the pair of working belts comprises a first working belt and a second working belt located radially outside the first working belt, wherein the middle belt is disposed between the first working belt and the second working belt and comprises elongated reinforcing elements having an angle with the tire circumferential direction of less than 5°. Still according to the third aspect, the middle belt has a rubber permeability of at least 90% along at least 90% of its axial width, and the belt portion comprises a top belt disposed radially above the second working belt, wherein the top belt comprises cords having an impact energy absorption greater than 7 J / mm 2 .

[0006] The present application provides the following technical solutions:

[0007] 1. A tire comprising a tread and a belt portion located radially below the tread,

[0008] wherein the tread has two shoulder portions each comprising a shoulder groove,

[0009] wherein the belt portion comprises a pair of working belts and a middle belt,

[0010] wherein the pair of working belts comprises a first working belt and a second working belt disposed radially above the first working belt,

[0011] wherein the intermediate belt layer is arranged between the first working belt layer and the second working belt layer and has elongated reinforcing elements having an angle of less than 5° to the circumferential direction of the tire, and wherein the intermediate belt layer comprises a first layer and one or more further layers, wherein the first layer of the intermediate belt layer extends to cover at least 70% of the axial width of the axially largest of the pair of working belt layers, and wherein each of the one or more further layers of the intermediate belt layer is arranged radially below one of the shoulder grooves and extends to cover at most 50% of the axial width of the axially largest working belt layer, and

[0012] wherein the belt portion further comprises a top belt layer arranged radially above the second working belt layer, wherein the top belt layer comprises reinforcing cords having an impact energy absorption of higher than 7 J / mm 2 .

[0013] 2. The tire of aspect 1, wherein a second layer of the one or more further layers is arranged radially below the first shoulder groove and a third layer of the one or more further layers is arranged radially below the second shoulder groove, wherein each of the first, second, and third layers is formed from a spirally wound ply strip.

[0014] 3. The tire of aspect 2, wherein the first, second, and third layers are formed from a single ply strip.

[0015] 4. The tire of aspect 2, wherein the second layer is radially below the first layer and the third layer is radially above the first layer.

[0016] 5. The tire of aspect 2, wherein the second and third layers are one of: both radially below the first layer; and both radially above the first layer.

[0017] 6. The tire of aspect 1, wherein the elongated reinforcing elements are one or more of a metal cord and a metal wire.

[0018] 7. The tire of aspect 1, wherein the reinforcing cords of the top belt layer comprise a steel cord having a cord structure of 5xd, where d is in the range of 0.3 mm to 0.5 mm.

[0019] 8. The tire of aspect 1, wherein the elongated reinforcing elements of the intermediate belt layer are ultra-high tensile steel cords.

[0020] 9. The tire of aspect 1, wherein the elongated reinforcing elements of the intermediate belt layer are steel cords having a cord structure according to a + b x d, where a is in the range of 1 to 5, b is in the range of 2 to 7, and d is in the range of 0.2 mm to 0.5 mm.

[0021] 10. Tire according to solution 1,

[0022] wherein the elongated reinforcing elements of the intermediate belt layer are metal cords,

[0023] wherein the working belt layer comprises metal cords, and

[0024] wherein the elongation at 10% of the breaking force of the metal cords of the intermediate belt layer and of the metal cords of the working belt layer is higher than 0.2% and lower than 0.4%, said elongation being measured after extraction from the vulcanized tire.

[0025] 11. Tire comprising a tread and a belt portion located radially below the tread,

[0026] wherein the tread has two shoulder portions, each shoulder portion comprising a shoulder groove,

[0027] wherein the belt portion comprises a pair of working belt layers and an intermediate belt layer,

[0028] wherein the pair of working belt layers comprises a first working belt layer and a second working belt layer located radially above the first working belt layer,

[0029] wherein the intermediate belt layer is arranged between the first working belt layer and the second working belt layer and comprises metal cords having i) an angle with the tire circumferential direction of less than 5° and ii) a cord structure according to a + b x d, wherein a ranges from 1 to 5, b ranges from 2 to 7 and d ranges from 0.2 mm to 0.5 mm, and

[0030] wherein the belt portion further comprises a top belt layer arranged radially above the second working belt layer, wherein the top belt layer comprises cords having an impact energy absorption rate greater than 7 J / mm 2

[0031] 12. Tire according to solution 11,

[0032] wherein the metal cords of the intermediate belt layer are ultra-high tensile steel cord having a structure selected from one or more of 4+3x0.35 and 3+2x0.35;

[0033] wherein the working belt layer comprises steel cords; and

[0034] wherein the elongation at 10% of the breaking force of the steel cords of the intermediate belt layer and of the steel cords of the working belt layer is higher than 0.2% and lower than 0.4%, said elongation being measured after extraction from the vulcanized tire.

[0035] ​13. The tire according to aspect 11, wherein the intermediate belt layer comprises at least two layers, including a first layer and one or more additional layers, wherein the first layer of the intermediate belt layer extends to cover at least 70% of the axial width of the axially maximum working belt layer, and wherein each of the one or more additional layers of the intermediate belt layer is arranged radially below one of the shoulder grooves and extends to cover at most 50% of the axial width of the axially maximum working belt layer.

[0036] 14. The tire according to aspect 13, wherein the first layer and the one or more additional layers are formed together from a single spirally wound ply strip having a width in the range of 1.5 to 25 mm, a radial thickness in the range of 0.5 to 3 mm, and comprising 1 to 5 parallel ultra-high tensile steel cord wires.

[0037] 15. A tire comprising a tread and a belt portion located radially below the tread,

[0038] wherein the tread has two shoulder portions, each shoulder portion comprising a shoulder groove,

[0039] wherein the belt portion comprises a pair of working belt layers and an intermediate belt layer,

[0040] wherein the pair of working belt layers comprises a first working belt layer and a second working belt layer located radially above the first working belt layer,

[0041] wherein the intermediate belt layer is arranged between the first working belt layer and the second working belt layer and comprises elongated reinforcing elements having an angle to the circumferential direction of the tire of less than 5°, and

[0042] wherein the intermediate belt layer has a rubber permeability of at least 90% along at least 90% of its axial width, and

[0043] wherein the belt portion further comprises a top belt layer arranged radially above the second working belt layer, and the top belt layer comprises cords having an impact energy absorption of greater than 7 J / mm 2

[0044] 16. The tire according to aspect 15, wherein the elongated reinforcing elements are metal cords having a cord structure according to a + b x d, wherein a ranges from 3 to 5, b ranges from 2 to 4, and d ranges from 0.2 mm to 0.5 mm.

[0045] 17. The tire according to aspect 16, wherein the elongated reinforcing elements are steel cord wires.

[0046] 18. The tire according to aspect 17, wherein the steel cord wires are ultra-high tensile steel cord wires.​

[0047] 19. The tire according to solution 18, wherein the ultra-high tensile steel cord has a construction selected from one of 4+3x0.35 and 3+2x0.35.

[0048] 20. The tire according to solution 15, wherein the axial width of the top belt layer is from 80% to 95% of the maximum axial width of the intermediate belt layer, and wherein the maximum axial width of the intermediate belt layer is at most 95% of the maximum axial width of the axially narrowest working belt layer of the pair of working belt layers. BRIEF DESCRIPTION OF DRAWINGS

[0049] The application will be described by way of example and with reference to the accompanying drawings, in which:

[0050] Figure 1 is a schematic cross-sectional view of a tire according to a first embodiment of the application;

[0051] Figure 2 is a schematic cross-sectional view of another tire according to a second embodiment of the application;

[0052] Figure 3 is Figure 1 and Figure 2 is a schematic cross-sectional view of an alternative belt portion of one of the tires of

[0053] Figure 4 is Figure 1 and Figure 2 is another schematic cross-sectional view of another alternative belt portion of one of the tires of

[0054] Figure 5 is Figure 1 and Figure 2 is yet another schematic cross-sectional view of a third alternative belt portion of one of the tires shown in DETAILED DESCRIPTION

[0055] According to a first aspect, the (preferably pneumatic) tire comprises a tread and a belt portion located radially below the tread. The tread has two shoulder portions, or axially opposite shoulder portions, wherein each shoulder portion comprises a shoulder groove (in particular extending in the circumferential direction of the tire). The belt portion comprises a pair of working belts and a center belt, wherein the pair of working belts comprises a first working belt and a second working belt disposed radially above the first working belt. The center belt is disposed between the first working belt and the second working belt and has elongated reinforcing elements having an angle to the circumferential direction of the tire of less than 5° (preferably less than 2° or less than 1°), wherein the center belt comprises a first layer and one or more further layers. The first layer of the center belt extends to cover at least 70% (preferably at least 75% and / or less than 95%) of the axial width of the axially widest working belt of the pair of working belts, and each of the one or more further layers of the center belt is arranged radially below one of the shoulder grooves and extends to cover at most 50% (preferably at most 30%, and / or preferably at least 5%) of the axial width of the axially widest working belt. Furthermore, the belt portion comprises a top belt arranged radially above the second working belt, the top belt comprising reinforcing cords having an impact energy absorption of more than 7 J / mm 2 , preferably more than 7.5 J / mm 2 .

[0056] The inventors found that this combination of a center belt and a top belt results in a particularly strong tire design. In particular, the combination of the center belt and the top belt comprises reinforcing cords having a high impact energy absorption, which helps to provide a tire that is particularly durable at the circumferential centerline of the tire, thereby helping to avoid tread groove cracks at the circumferential centerline of the tire.

[0057] The impact energy absorption is herein determined as the impact energy absorption using a Charpy impact test, for example using an energy / cord (or in other words, energy absorption / cord, or in particular impact energy absorption / cord) of 1 inch strip having 10 ends per inch (EPI).

[0058] In one embodiment, a second layer of the one or more further layers is disposed radially below the first shoulder groove, and a third layer of the one or more further layers is disposed radially below the second shoulder groove, wherein each of the first, second, and third layers is formed from a spirally wound ply strip.

[0059] It has been found that this tire structure, with a pair of working belt layers and an intermediate belt layer, in particular comprising a layer arranged radially below the shoulder grooves, further improves the robustness of the tire, in particular the corresponding shoulder regions of the tire, including the tread and / or belt portions. In particular, this multi-layer design of the intermediate belt layer contributes to improving the durability of the intermediate belt layer in the corresponding shoulder regions of the tire.

[0060] In another embodiment, the first layer, the second layer and the third layer are formed by a single ply strip. The ply strip is preferably a wound ply strip. It can be seen as being wound around the axial direction of the tire (e.g. spirally / helically wound), thereby forming at least one of the layers of the intermediate belt layer. The strip can be wound at an angle of less than 5° with the circumferential direction of the tire. Preferably, such angle is between 0.1° and 4°, more preferably between 0.1° and 2°, or even more preferably between 0.2° and 1°. The angle is preferably the same angle as the angle of the parallel and / or elongated reinforcing elements of the ply strip. The reinforcing elements of the ply strip are preferably coated with a (coating) rubber composition to form the ply strip. In other words, the ply strip comprises reinforcing elements coated with a rubber composition. Similarly, the belt layers typically comprise reinforcing elements, such as cords (e.g. metal cords and / or steel cords), which are coated with a rubber composition. Rubber compositions (or in other words, rubber coating compositions) for use in the belt layers, or in other words, the belt plies and the ply strip, are known in the tire art.

[0061] In another embodiment, the axial width over which each of the one or more further layers (e.g. the second layer and / or the third layer) extends corresponds to 5% to 30% (preferably 5% to 20%) of the (maximum) axial width of the axially maximum working belt layer. Alternatively, or in addition, the axial width over which each of the one or more further layers (e.g. the second layer and / or the third layer) extends corresponds to a range of 90% to 300% (preferably 100% or 110% to 250%) of the axial width of the (radially outer or outermost) opening of the respective shoulder groove located radially above the respective further layer of the intermediate belt layer.

[0062] In another embodiment, the one or more further layers comprise a second layer arranged radially below the first shoulder groove and a third layer arranged radially below the second shoulder groove. Preferably, the intermediate belt layer comprises only these three layers.

[0063] In another embodiment, the tread comprises four or five (preferably four) circumferential grooves, including two shoulder grooves, wherein one of the shoulder grooves is located in each of the axially / laterally outer regions of the tread.

[0064] In yet another embodiment, the axial maximum working belt layer, which is preferably the radially innermost working belt layer, extends over an axial width in the range of 110% to 200%, preferably from 115% to 160% of the axial distance between the axial (and radial) outer edges of the shoulder groove. The axial (and radial) outer edges of the shoulder groove can also be described as the axial outer edges of the radially outer openings of such grooves.

[0065] In another embodiment, each of the first, second and third layers is formed from at least one ply strip comprising reinforcing elements. Each layer can be formed from one or more individual ply strips. Optionally, each strip is wound and / or constructed as described above.

[0066] In another embodiment, the first, second and third layers are formed from the same ply strip. For example, the second layer can be spirally wound from an axially inner position over the radially underlying working belt layer to a first axially outer position. From the first axially outer position, the strip is radially wound over the second layer in an axially inner direction, thereby forming the first layer covering at least 70% of the axial width of the axially maximum working belt layer. From a second axially outer (or outermost) position of the first layer, e.g. at the opposite axial / transverse side of the tire, the axial winding direction of the strip is reversed in order to provide the third layer over the first layer. Providing all three layers with one strip is particularly fast and / or economically efficient. Moreover, it is also possible to construct different tire widths and diameters in this way, e.g. using only a single strip type.

[0067] In another embodiment, one or more of the first, second and third layers are each formed from at least one individual ply strip.

[0068] In yet another embodiment, the second layer is located radially below the first layer and the third layer is located radially above the first layer. This preferred construction is easy to manufacture in one strip winding step.

[0069] In yet another embodiment, the second and third layers are one of the following: i) both located radially below the first layer; ii) both located radially above the first layer. The second and third layers can also be provided at substantially the same radial height. However, each of the second and third layers is preferably formed in a circumferential band radially below each shoulder groove or shoulder of the tire. The location radially below each shoulder groove or shoulder of the tire does not exclude the provision of one or more further belt layers radially above the second and / or third layer and between the second and / or third layer and the shoulder groove.

[0070] In yet another embodiment, the elongated reinforcing elements are one or more of metal cords and metal filaments, preferably metal cords, such as steel cord.

[0071] In yet another embodiment, the top belt includes a rubber composition reinforced by cords (e.g., metal, preferably steel, textile or hybrid cords).

[0072] In yet another embodiment, the reinforcing cords of the top belt include metal cords, preferably steel cords, having a cord structure according to 5 x d, d ranging from 0.3 mm, preferably from 0.34 mm or from 0.35 mm to 0.5 mm, for example 5 x 0.35 mm and / or 5 x 0.38 mm. Additionally, or alternatively, the reinforcing cords of the top belt include metal cords, preferably steel cords, having a lay length in the range of 10 mm to 20 mm, preferably in the range of 12 mm to 16 mm, or even more preferably in the range of 13 mm to 15 mm.

[0073] In yet another embodiment, the elongated reinforcing elements of the intermediate belt (and / or working belt) are steel cords. In yet another embodiment, the steel cords are one of an ultra-high tensile steel cord and an ultra-strong tensile steel cord, preferably an ultra-high tensile steel cord. Ultra-strong tensile steel cord refers to a steel cord (preferably carbon steel) having a tensile strength of at least 4050 MPa - (2000 MPa / mm x D), where D is the filament diameter in mm and x denotes multiplication. Ultra-high tensile steel cord refers to a steel cord (preferably carbon steel) having a tensile strength of at least 4400 MPa - (2000 MPa / mm x D), where D is also the filament diameter in mm and x denotes multiplication.

[0074] In yet another embodiment, the elongated reinforcing elements of the intermediate belt are steel cords having a cord structure according to a + b x d, where a is an integer in the range of 1 to 5 (preferably 3 to 5), b is an integer in the range of 2 to 7 (preferably 2 to 4) and d ranges from 0.2 mm to 0.5 mm.

[0075] In yet another embodiment, the cords of the working belt and / or intermediate belt are metal cords having a structure a + b x d, where a ranges from 2 to 5 (metal filaments / filaments), b ranges from 2 to 4 (metal filaments / filaments), d (the respective diameter of the metal filaments / filaments) ranges from 0.2 mm to 0.5 mm (preferably from 0.3 mm to 0.45 mm). In particular, such a structure is considered to be open to rubber penetration, which further improves the robustness of the tire.

[0076] In yet another embodiment, the elongated reinforcing elements of the intermediate belt are metal (preferably steel) cords, and / or the working belt includes metal (preferably steel) cords (or reinforcing cords).

[0077] In yet another embodiment, the metal cords of the intermediate belt and working belt have the same cord structure.

[0078] In yet another embodiment, one or more metal cords (e.g. of the intermediate and / or working belt layers) have an elongation at 10% of their breaking force higher than 0.2% or 0.21%, preferably lower than 0.4%, or 0.35%, or 0.3%, or even lower than 0.29%, the elongation being measured after extraction from the cured tire. Preferably, these values apply to the cords of the working belt layers and / or the cords of the intermediate belt layers. Such cord elongation or tensile tests on cords are herein performed according to ISO 6892-1 B with a pre-tension of 20 MPa.

[0079] In yet another embodiment, the intermediate belt layer (including its plies) is radially disposed between the two working belt layers of the pair of working belt layers.

[0080] In yet another embodiment, the ply strip has an axial width in the range of 1.5 millimeters to 25 millimeters, preferably from 3 millimeters to 16 millimeters, or from 3 millimeters to 9 millimeters, and / or a radial thickness in the range of 0.5 millimeters to 3 millimeters, preferably from 1 millimeter to 3 millimeters. Such radial thickness values also apply to the other belt layers or belt plies mentioned herein, including one or more of the working belt layers, the transition belt layer (if any), and the top belt layer.

[0081] In yet another embodiment, the ply strip comprises from 1 (preferably from 2) to 5 parallel reinforcing elements selected from one or more of cords and wires.

[0082] In yet another embodiment, the ply strip has a density of parallel reinforcing elements in the range of 10 ends per inch (EPI) to 20 EPI, e.g. measured perpendicular to the elongate extension of the strip, and / or measured perpendicular to the elongate extension of the reinforcing elements.

[0083] In yet another embodiment, the working belt layer has a density of parallel reinforcing elements in the range of 8 EPI to 15 EPI, preferably from 10 EPI to 14 EPI, measured perpendicular to the elongate extension of the reinforcing elements.

[0084] In yet another embodiment, the reinforcing elements are one or more of: elongate reinforcing elements; metal reinforcing elements; metal and / or hybrid cords, optionally comprising a plurality of metal wires / filaments. The preferred metal herein is steel. The metal reinforcing elements or cords can optionally be coated with brass. In the most preferred embodiment, the reinforcing elements are brass-coated steel wire cords, e.g. comprising a plurality of steel wires.

[0085] In yet another embodiment, each working belt layer of the pair of working belt layers comprises parallel (and preferably elongated) reinforcing elements, wherein the reinforcing elements of the first working belt layer and the reinforcing elements of the second working belt layer cross each other at opposite angles, or in other words, are oriented at opposite angles to each other.

[0086] In yet another embodiment, the absolute value of the angle of the (respective) reinforcing elements (or cords) of each working belt layer with the tire circumferential direction ranges from 10° to 50°, preferably from 15° to 30°, or more preferably from 15° to 25°. Alternatively, or in addition, the difference between i) the absolute value of the angle of the reinforcing elements of the first working belt layer and ii) the absolute value of the angle of the reinforcing elements of the second working belt layer is at least 2° (preferably at least 3° and / or at most 15°, or at most 8°, or only at most 6°). Preferably, the radially innermost working belt layer has the larger absolute angle. For example, the angle is preferably made closer to the angle of at least one of the body plies, which preferably has an angle of 90° with the circumferential direction. Preferably, in such embodiments, the belt portion does not have a transition belt layer between the radially innermost working belt layer and the adjacent body ply, which transition belt layer is disposed radially below said innermost working belt layer.

[0087] In yet another embodiment, each working belt layer of the pair of working belt layers comprises parallel (elongated) reinforcing elements, wherein at least one of i) the reinforcing elements of the working belt layers and ii) the reinforcing elements of the intermediate belt layer, but preferably both, have a relative elongation at break / at 10% of the break force of less than 0.4% (preferably less than 0.3% or less than 0.29%). Optionally, said elongation is at least 0.2% or 0.21%.

[0088] In yet another embodiment, the reinforcing cords of the top belt layer have an angle with the tire circumferential direction in the range of 10° to 25°, preferably 14° to 21°. In addition, or alternatively, the top belt layer is axially narrower than each of the working belt layers and the first layer of the intermediate belt layer.

[0089] In yet another embodiment, the belt portion has exactly four belt layers, namely two working belt layers, an intermediate belt layer (with multiple layers, preferably exactly three layers) and a top belt layer; or exactly five belt layers, including said four belt layers and a transition belt layer arranged radially below the radially innermost working belt layer.

[0090] In yet another embodiment, the axial width of the top belt is at least 50% of the axial width of the axially outermost working belt and / or the radially innermost working belt, which is preferably the axially outermost working belt. Additionally, or alternatively, the axial width of the top belt is in the range of 50% to 90%, or 50% to 85%, preferably 50% to 80%, of the axial width of the axially outermost working belt and / or the radially innermost working belt. Additionally, or alternatively, the axial width of the top belt is in the range of 75% to 90%, preferably 80% to 85%, of the (maximum) axial width of the intermediate belt.

[0091] In yet another embodiment, the tire further comprises a transition belt arranged radially below the pair of working belts. Optionally, the transition belt comprises parallel reinforcing elements having an angle to the tire circumferential direction in the range of 35° to 90°, preferably 50° to 90°, or more preferably 50° to 75°. Preferably, the transition belt is axially narrower than each of the working belts and the first layer of the intermediate belt.

[0092] In yet another embodiment, the transition belt comprises metal cords, preferably steel cords, having a structure of 3+2x0.35. Additionally, or alternatively, the metal cords of the transition belt are steel cords having a cord structure according to a+b x d, wherein a is in the range of 1 to 5, preferably 3 to 5, b is in the range of 2 to 7, preferably 2 to 4, and d is in the range of 0.2 mm to 0.5 mm (wherein a and b are also integers).

[0093] In yet another embodiment, both working belts have a larger axial width than the intermediate belt.

[0094] In yet another embodiment, the tire comprises one of i) four belts (i.e. one top belt, two working belts, and one intermediate belt) and ii) five belts (i.e. one top belt, two working belts, one intermediate belt, and one transition belt).

[0095] In yet another embodiment, the tire further comprises a rubbery ply disposed between the radially inner working belt layer and the radially outermost carcass ply of the tire. Such rubbery ply is preferably free of reinforcing material. Optionally, it has a radial thickness in the range of 0.5 mm to 3 mm, preferably in the range of 1 mm to 2.5 mm. Preferably, it has a stiffness at most that of the rubber composition of the radially inner working belt layer. Preferably, such stiffness of the rubber composition of the rubbery ply is at least 5% lower than the stiffness of the rubber composition of the radially inner working belt layer. Herein, stiffness is determined as G'(1%). Herein, G'(1%) is at 100°C and 1 Hz, 1% strain, using an Alpha Technologies' RPA 2000 TM The rubber processing analyzer is obtained based on ASTM D5289 or equivalent standard.

[0096] In yet another embodiment, one or more of the first, second, and third layers (of the intermediate belt layer) do not extend axially beyond the adjacent axially outer (outermost) edge of the one or more working belt layers.

[0097] In yet another embodiment, one or more of the first, second, and third layers extend axially beyond the adjacent axially outer edge of the top belt layer. Preferably, one or more of the first, second, and third layers extend axially beyond the axially outer edge of the top belt layer by less than 10% (preferably less than 5%) of the total axial width of the top belt layer.

[0098] In yet another embodiment, the belt portion has one or more of the following: the first layer of the intermediate belt layer is greater in the axial direction than the top belt layer; the second working belt layer is greater in the axial direction than the first layer; and the first working belt layer is greater in the axial direction than the second working belt layer.

[0099] In another embodiment, each belt layer extends in an axially outward direction so as to support a shoulder groove on each lateral / axial side of the tire. In other words, each belt layer (including the top belt layer, among others) optionally extends to an outer axial position that is axially outward of the radially outermost end (or opening) of the axially outer wall of the respective shoulder groove.

[0100] In yet another embodiment, one or more of the top belt layer, the first working belt layer, the second working belt layer, and the intermediate belt layer extend (preferably continuously extend, and / or extend transverse to the radial direction / equatorial plane of the tire) from a radially inferior position of a first shoulder portion of the two shoulder portions to another radially inferior position of a second shoulder portion of the two shoulder portions. Additionally, or alternatively, the two axially outer edges of the one or more belt layers are substantially symmetrical about the equatorial plane of the tire.

[0101] In yet another embodiment, the rubber permeability of at least one of the working belt and / or the intermediate belt is at least 90%, preferably at least 95%, or even more preferably at least 99% or 100%. Full rubber permeation improves the durability of the tire and enhances the resistance to corrosion and retreading. Moreover, such high rubber permeability provides even higher durability of the respective belt and helps to avoid cord breakage.

[0102] The reinforcing cords of the belt are usually coated with a rubber composition or rubber mixture before tire assembly. During the curing or vulcanization process, the rubber penetrates the cords. The extent of rubber penetration of the free zones of the cords, referred to as rubber permeability, is expressed as the percentage of the free zones occupied by the rubber mixture after vulcanization and determined by a gas permeability test. This test is performed on cords extracted from the belt of a vulcanized tire, thus, the cords have been penetrated by the vulcanized rubber composition. Rubber permeability is measured herein by a gas permeability test according to L. Bourgois, Investigation of the Mechanical Properties of Steel Cord and Related Test Methods, Special Technical Publication 694, ASTM, 1980, or equivalent standard.

[0103] In yet another embodiment, the tire is one or more of the following: a pneumatic tire; a radial tire; one of a 17.5, 19.5, 22.5 and 24.5 inch tire; a truck tire; a tire having at least one steel wire reinforced carcass ply; a tire comprising a working belt reinforced with steel wires and / or a reinforcing intermediate belt formed of steel wire reinforced plies. Preferably, the tire is a 22.5 inch pneumatic radial truck tire.

[0104] In yet another embodiment, the second layer and / or the third layer are arranged axially outside of the respective shoulder groove of the respective shoulder portion.

[0105] In yet another embodiment, the tire can be constructed by a method comprising one or more of the following steps:

[0106] providing at least one carcass ply, for example on a tire building drum;

[0107] optionally applying a transition belt to the carcass ply;

[0108] applying a first working belt to the carcass ply and / or the transition belt;

[0109] applying an intermediate belt to the first working belt, preferably comprising one or more of the following sub-steps a) to c):

[0110] a) in a first wrapping step, wrapping a strip of plies around (or about) a first working belt layer to form a circumferential band (or layer) of the intermediate belt layer extending over an axial portion of the first working belt layer, radially below a first shoulder portion of the shoulder portion and / or a first shoulder groove of the shoulder grooves (wherein the axial width of said band or layer is preferably at most 50% or 30% (and / or at least 5%) of the axial width of the first working belt layer);

[0111] b) in a second wrapping step, continuing to wrap the same strip of plies (preferably in an axial orientation opposite to that of the first wrapping step) to form a further layer of the intermediate belt layer covering at least 70% (and / or at most 95%) of the first working belt layer width, and preferably also covering said band or layer formed in the first wrapping step;

[0112] c) in a third wrapping step, continuing to wrap the same strip of plies (preferably in the same axial orientation as in the first wrapping step) to form a further circumferential band (or layer) of the intermediate belt layer extending over an axial portion of the intermediate belt layer and / or said further layer formed in the second wrapping step, radially below a second shoulder portion and / or a second shoulder groove (on the side of the tire axially opposite to said first shoulder portion and / or groove), wherein the axial width of said further band (or layer) is preferably at most 50% or 30% (and / or at least 5%) of the axial width of the first working belt layer;

[0113] applying a second working belt layer to the intermediate belt layer;

[0114] applying a top belt layer to the second working belt layer, wherein the second working belt layer and the top belt layer can optionally be applied together as one member to the intermediate belt layer;

[0115] applying a tread to the top belt layer.

[0116] In one embodiment, the first, second and third wrapping steps are performed consecutively, for example in one pass.

[0117] In another embodiment, the wrapping is a spiral wrapping, for example wrapping around the axial direction, and / or as described in other paragraphs herein.

[0118] It is emphasized that these features of building the tire are not limited to the above steps, and that these steps do not exclude additional manufacturing or mounting steps of additional tire components, such as sidewalls, chafer, bead, apex, cover, etc. These steps can also be present between one or more of the above steps.

[0119] In another embodiment, the tire further comprises one or more of two axially spaced apart bead portions (wherein, for example, each bead portion comprises one or more beads and a bead apex), two sidewalls (wherein each of the two sidewalls extends between the tread and a respective one of the bead portions), one or more carcass plies extending from one of the bead portions to the other of the bead portions (wherein, optionally, at least one of the carcass plies is folded around each bead, and / or wherein the belt portion is disposed radially outwardly or radially above the one or more carcass plies in a crown region of the tire), and an innerliner layer at least partially enclosing a tire cavity.

[0120] According to a second aspect, the tire comprises a tread and a belt portion located radially below the tread, wherein the tread has two (e.g., axially opposite) shoulder portions, each shoulder portion containing (circumferentially extending) shoulder grooves, wherein the belt portion comprises a pair of working belts and a middle belt. Further, the pair of working belts comprises a first working belt and a second working belt located radially above the first working belt, the middle belt being disposed between the first working belt and the second working belt and containing metal cords having the following characteristics: i) an angle of less than 5° (preferably less than 2° or 1°) to the circumferential direction of the tire; ii) a cord structure according to a + b x d, wherein a ranges from 1 to 5 (preferably 3 to 5), b ranges from 2 to 7 (preferably 2 to 4), and d ranges from 0.2 mm to 0.5 mm. Further, the belt portion comprises a top belt disposed radially above the second working belt, wherein the top belt comprises cords having an impact energy absorption of greater than 7 J / mm 2 , preferably greater than 7.5 J / mm 2 .

[0121] It has been found that the provision of such a middle belt cord in combination with the top belt cord provides a very strong belt design. In particular, the cord structure of the middle belt provides a high rubber permeability.

[0122] In one embodiment, the metal cords of the middle belt are ultra-high tensile steel cord having a structure selected from one or more of 4+3x0.35 and 3+2x0.35, and / or the working belts contain steel cords. Optionally, the steel cords of the middle belt and the steel cords of the working belts have an elongation at 10% of their breaking force that is higher than 0.2% and lower than 0.4%, measured after extraction from the vulcanized tire. Optionally, a narrower elongation range can be applied, for example the range mentioned above.

[0123] In another embodiment, the intermediate belt layer comprises at least two layers, including a first layer and one or more further layers, wherein the first layer of the intermediate belt layer extends to cover at least 70% of the axial width of the axially widest working belt layer, and wherein each of the one or more further layers of the intermediate belt layer is arranged radially below one of the shoulder grooves and extends to cover at most 50% of the axial width of the axially widest working belt layer.

[0124] In yet another embodiment, the first layer and the one or more further layers are formed together from a single and / or preferably spirally wound ply strip having one or more of the following characteristics: an axial width in the range of 1.5 to 25 mm, a radial thickness in the range of 0.5 to 3 mm, and 1 to 5 parallel, preferably ultra-high tensile steel cord filaments.

[0125] According to a third aspect, the tire comprises a tread and a belt portion located radially below the tread, wherein the tread has two (e.g., axially opposite) shoulder portions each containing a (circumferentially extending) shoulder groove, wherein the belt portion comprises a pair of working belt layers and an intermediate belt layer. Further, the pair of working belt layers comprises a first working belt layer and a second working belt layer disposed radially outward of the first working belt layer, wherein the intermediate belt layer is disposed between the first working belt layer and the second working belt layer and comprises elongated reinforcing elements having an angle with the circumferential direction of the tire of less than 5° (preferably less than 2° or 1°). Still according to the third aspect, the intermediate belt layer has a rubber permeability of at least 90% (preferably at least 95%, or even 99%) along / at least 90% of its axial width (or preferably its entire axial width). Further, the belt portion comprises a top belt layer arranged radially above the second working belt layer, which comprises cord filaments having an impact energy absorption of more than 7 J / mm 2 , preferably more than 7.5 J / mm 2 .

[0126] The advanced rubber permeability of the intermediate belt layer cord filaments, in combination with the high impact resistance, or in other words, the impact energy absorption, of the cord filaments in the top belt layer, jointly result in a very robust belt portion design, especially in the axially central portion of the tire. This also helps to avoid cracks in the axially central portion of the tire tread.

[0127] In one embodiment, the elongated reinforcing elements are metal cord filaments having a cord structure according to a + b x d, wherein a is an integer in the range from 1 (preferably from 3) to 5, b is an integer in the range from 2 to 7 (preferably to 4), and d is in the range from 0.2 mm to 0.5 mm.

[0128] In another embodiment, the elongated reinforcing elements are steel cords, preferably ultra-high tensile steel cords.

[0129] In yet another embodiment, the ultra-high tensile steel cords have a construction selected from one of 4+3x 0.35 and 3+2x 0.35.

[0130] In yet another embodiment, the axial width of the top belt layer is from 80% to 95% of the maximum axial width of the intermediate belt layer; and / or the maximum axial width of the intermediate belt layer is at most 95% of the maximum axial width of the axially narrowest working belt layer of the pair of working belt layers; and / or the two axially opposite edges of the top belt layer are substantially symmetrical about the equatorial plane of the tire (or in other words, the two edges have a distance from the equatorial plane of the tire which is substantially equal, measured perpendicular to the equatorial plane of the tire).

[0131] In yet another embodiment, one or more (preferably each) of the top belt layer, the first working belt layer, the second working belt layer and the intermediate belt layer extend (preferably continuously extend, and / or extend transverse to the radial direction / equatorial plane of the tire) from a radially lower position of a first of the two shoulder portions to another radially lower position of a second of the two shoulder portions. Additionally, or alternatively, the two axially outer edges of the one or more belt layers are substantially symmetrical about the equatorial plane of the tire.

[0132] Figure 1 A tire 1 according to a preferred embodiment of the present application is shown. The tire 1 has a tread 20, a pair of sidewalls 30, a pair of bead portions 40, a carcass ply 50 and an innerliner 60. Each bead portion 40 comprises a bead 41 and a bead apex 42. Furthermore, the tire 1 has a belt portion 100 comprising a plurality of belt layers, including a first working belt layer 110, a second working belt layer 130, an intermediate belt layer 120 and a top belt layer 140. According to Figure 1 the embodiment, the intermediate belt layer 120 comprises three layers, namely a first layer 121, a second layer 122 and a third layer 123. Each of the second layer 122 and the third layer 123 is arranged radially below a respective shoulder groove 21 of the tread 20.

[0133] Each of the first working belt layer 110 and the second working belt layer 130 has parallel and elongated reinforcing elements or reinforcing elements, in this case metal cords, which have an angle to the circumferential direction c in the range of 10° to 50°. The reinforcing elements of the first working belt layer 110 cross the reinforcing elements of the second working belt layer 130 with an opposite angle orientation, wherein, in a preferred embodiment, the angle of the first working belt layer 110 to the circumferential direction c is 4° larger than the angle of the second working belt layer 130 to the circumferential direction c.

[0134] AsFigure 1 The diagram schematically illustrates that the intermediate belt layer comprises at least one fabric layer strip wound to form the intermediate belt layer 120. Specifically, the angle between the metal cords of the intermediate belt layer 120 (particularly in the fabric layer strip of the intermediate belt layer 120) and the circumferential direction c is less than 1° in this example. The fabric layer strip is helically wound around the circumferential first working belt layer 110 about the axial direction a. Figure 1 In the preferred embodiment shown, the entire intermediate belt layer 120 (comprising three layers) is formed from a single fabric strip.

[0135] Specifically, this ply strip can be spirally wound from the axially inner position to the axially outer end position, thereby forming a second layer 122. After reaching the axially outer end position of the second layer 122, the ply strip can be wound around the axial direction of the tire 1, but during the continued winding process, the ply strip moves in the axially inner direction, thereby forming a first layer 121. Figure 1 (From left to right). After the ply strip continues to wind radially above the first working belt layer 110, the axial outward movement during the winding process stops, and it reverses again at the axially outer end position on the right side of the tire 1, thereby continuing to move axially inward towards the tire 1 during the winding process. Through this axial inward movement, the third layer 123 of the intermediate belt layer 120 can be formed. Finally, once the desired width of the third layer 123 has been obtained, the axial inward movement and winding can be stopped.

[0136] In this embodiment, each of the second and third layers at least covers the bottom of the corresponding shoulder groove located radially above the second layer 121 and the third layer 123. The total axial width of the intermediate belt layer 120 is preferably greater than the total axial width of the top belt layer 140, for example, at least 1% and / or at most 10% greater axially than the top belt layer 140. The width of the first working belt layer 110 is greater than the width of the second working belt layer 130, preferably in the range of 5% to 20% greater. On the other hand, the total axial width of one of the second layer 122 and the third layer 123 of the intermediate belt layer 120 is preferably in the range of 10% to 30% of the axial width of the first working belt layer 110 (in this example, the belt layer with the largest axial direction of the belt layer portion 100). On the other hand, the width of the second layer 122 or the third layer 123 of the intermediate belt layer 120 is preferably in the range of 90% to 250% of the axial width of the radially outermost opening of the corresponding shoulder groove 21 located radially above the second layer 122 or the third layer 123.

[0137] In the present embodiment, the top belt layer 140 is the axially narrowest belt layer of all belt layers 110, 120, 130, 140. Furthermore, the top belt layer comprises a plurality of reinforcing cords (here steel cords) having an impact energy absorption (per cord) higher than 7 J / mm 2 , for example about 7.8 J / mm 2 or about 8.4 J / mm 2 , as determined with a 1 inch strip having 10 EPI or equivalent gauge, on a Charpy impact machine as used herein. Furthermore, the steel cords of the top belt layer preferably have a structure of 5xd, d being in the range of 0.3 mm to 0.5 mm, for example 0.35 mm, or preferably 0.38 mm. In one alternative, the cords of the top belt layer can have an impact energy absorption lower than 15 J / mm 2 , for example lower than 12 J / mm 2 or lower than 10 J / mm 2 .

[0138] As shown in the present embodiment, it is preferred to have four belt layers in total. Furthermore, it is preferred that the tread 20 has four circumferential grooves. In another alternative embodiment, the tread has five such grooves.

[0139] The plies constituting the individual layers of the intermediate belt layer 120, or in other words the spirally wound plies, have a width in the range of 3 mm to 25 mm and a thickness in the range of 0.5 mm to 3 mm. In one preferred embodiment of the present application, the plies have a width of about 5 mm and a thickness of about 2 mm. In another specific embodiment, they have a width of 15 mm and a thickness of 2 mm.

[0140] For a better understanding, Figure 1 the axial direction a, the circumferential direction c and the radial direction r are indicated. The axial direction a is parallel to the axis of rotation of the tire. The circumferential direction c is parallel to the circumference of the tire, and the radial direction r is perpendicular to the axial direction a and the circumferential direction c. It is emphasized that each of these directions can have a different orientation, and therefore, a reference to one of these directions is not necessarily limited to a specific orientation, unless otherwise specified herein.

[0141] As mentioned above, Figure 1 the distances between the belt layers and / or layers shown in Figure 1 are shown larger than in reality. Thus, the gaps between the belt layers and / or between the belt layers shown are typically closed upon vulcanization of the tire. The same applies to the other figures shown herein. Figure 2 The tire 1 of

[0142] Figure 2Another embodiment of a pneumatic truck tire 10 according to the present application is schematically shown. Insofar as appropriate, Figure 1 the same reference numerals are used for the individual components, including the tread 20, the shoulder grooves 21, the sidewalls 30, the bead portions 40, the apex 42, the beads 41, the carcass ply 50 and the inner liner 60. Compared to the embodiment of the tire 1 shown, Figure 1 the tire 10 according to the present application has a different belt portion 200. This belt portion 200 comprises a first working belt 210, a second working belt 230, an intermediate belt 220 and a top belt 240. Figure 2 Figure 2 The intermediate belt 220 is not composed of three layers, but is a single layer formed of helically wound ply strips. In particular, it does not comprise two further layers arranged radially below each shoulder groove 21. However, the intermediate belt 220 also extends below each shoulder groove 21. Furthermore, the working belts 210, 230 each contain parallel metal cords, which are at an angle to the circumferential direction. The intermediate belt 220 contains metal cords, in particular ultra-high tensile steel cords, which have i) an angle to the circumferential direction of the tire of less than 5°, and ii) a cord structure of 4 + 3 x 0.35 (mm).

[0143] Similar to the previous embodiments, in the present embodiment the top belt 240 is the axially narrowest of the belts 210, 220, 230, 240. Furthermore, the top belt 240 contains a plurality of reinforcing steel cords, which again have a relatively high impact energy absorption per cord, which is preferably higher than 7.5 J / mm 2 Furthermore, the steel cords of the top belt 240 have a structure of 5 x 0.38 (mm). In the present embodiment, the twist pitch of these cords is about 14 mm.

[0144] Similar to the previous embodiments, in the present embodiment the top belt 240 is the axially narrowest of the belts 210, 220, 230, 240. Furthermore, the top belt 240 contains a plurality of reinforcing steel cords, which again have a relatively high impact energy absorption per cord, which is preferably higher than 7.5 J / mm 2 Furthermore, the steel cords of the top belt 240 have a structure of 5 x 0.38 (mm). In the present embodiment, the twist pitch of these cords is about 14 mm. Figure 3 In the present non-limiting embodiment, the absolute value of the angle of the parallel cords of the first working belt 210 is greater than the absolute value of the (opposite) angle of the parallel cords of the second working belt 230 by 4°. In particular, the cords of the first working belt 210 have an absolute angle of 23°, and the cords of the second working belt 230 have an absolute angle of 19°. It has been found that this combination of the pair of working belts 210, 230 and the intermediate belt arranged radially between the two working belts 210, 230 results in a more robust structure, further improving the robustness of the working belts. However, this feature is not mandatory.

[0145]

[0146] Figure 2An alternative belt portion 300 is shown which can be used in a tire, such as one of the above-described tires 1 or 10. The belt portion 300 includes a radially inner working belt 310, a radially outer working belt 330, an intermediate belt 320 disposed between the first working belt 310 and the second working belt 330, and a top belt 340 having the same steel cord as in the previous embodiments. The intermediate belt 320 includes a first layer 321, a second layer 322, and a third layer 323. In this embodiment, each layer is formed from a separate ply strip. The remaining structure can be the same or similar as described in relation to the embodiments of Figure 3 Figure 4 Embodiments of the same are also provided with second and third intermediate belts disposed radially below the upper shoulder grooves (not explicitly shown herein).

[0147] Figure 3 A further embodiment of a belt portion 400 is shown which includes a first working belt 410, a second working belt 430, an intermediate belt 420, and a top belt 440 having the same steel cord as in the previous embodiments. The intermediate belt 420 includes a first layer 421, a second layer 422, and a third layer 423, wherein each of the layers 421, 422, 423 is formed from a separate ply strip. Unlike the embodiment shown in Figure 3 the third layer is disposed radially above the first layer 421, and the second layer 422, 423 is disposed radially above the third layer 423. Figure 5 In the embodiment of

[0148] Figure 4 An embodiment of another possible belt portion 500 is shown which contains a similar belt as in the Figure 4 embodiments. In particular, the belt portion 500 includes a first working belt 510, a second working belt 530, an intermediate belt 520, and a top belt 540 which likewise contains steel cords having high impact energy absorption as described above. The intermediate belt 520 includes a first layer 521 and two radially outer layers 522 and 523 which are disposed radially above the first layer 521, and radially below the respective shoulder grooves (not explicitly shown here). In addition to the structure shown in Figure 5 the belt portion 500 of Figure 1 also has a filler layer 555 which is composed of a spirally wound rubber strip which is not reinforced, in particular does not contain textile or metal cords and / or wires. It can be used in the case of relatively thick layers of the intermediate belt, such as the second and / or third layers 522 and 523. However, this provision is not essential, since the individual belts of a tire are usually connected to one another during vulcanization of the tire. ​

[0149] In each of the non-limiting embodiments shown in the figures herein, the intermediate belt layer has elongated reinforcing elements in the form of metal cords, in particular steel cord, preferably coated with brass. In one preferred example, they have a cord structure of 4+3x0.35 (millimeters). In this example, the four inner filaments (or wires) are straight, and the three filaments are twisted over the four inner filaments, thereby providing a relatively open structure, for example, which enables good rubber (coating) penetration.

[0150] Preferably, the working belt layer has the same or similar cords as the intermediate belt layer. For example, the working belt layer can have a cord structure of preferably 4+3x 0.35 (millimeters), and / or 3+2x 0.35 (millimeters).

[0151] The number of ends per inch (EPI) of cords in the working belt layer preferably ranges from 8 EPI to 14 EPI. The number of ends per inch of the intermediate belt layer plies preferably ranges from 10 EPI to 20 EPI, preferably from 10 EPI to 16 EPI, or more preferably from 14 EPI to 16 EPI. Preferably, the EPI of cords in the top belt layer ranges from 8 EPI to 14 EPI, and / or is less than 10 EPI.

[0152] Preferably, the elongation (or relative elongation) of the cords used herein for the working belt layer and / or the intermediate belt layer at 10% of their breaking force is greater than 0.2%, and preferably less than 0.4%.

[0153] With regard to Figure 1 For the example of the present invention shown in the belt portion 100, the inventors performed a finite element analysis (FEA) comparing a tire having only the first layer of the intermediate belt layer (not shown) and ​ The tire shown has a third layer radially below the corresponding shoulder groove. This analysis concluded that by adding the third layer 123, the maximum force in the intermediate belt layer was reduced by about 25%, which is a significant improvement, contributing to the durability of the tire.

[0154] In addition, the inventors also tested the rubber penetration in the belt layers and in each of their layers used in the embodiments herein. The test results showed that the rubber penetration in the intermediate belt layer (including all its layers) reached 100% and covered the entire axial width. This is equally applicable to each of the working layers. Such very high rubber penetration makes the tire more robust and durable.

[0155] Overall, the present application and one or more of its optional embodiments help to provide a robust and durable tire, in particular a tire having an improved belt portion. For example, the stability of the shoulder portion and / or the respective groove area can be improved. Surprisingly, this also applies to the axially central belt portion and / or the tread provided above. Furthermore, a simple and / or cost-efficient manufacturing can be achieved. In particular, the energy and / or force absorption of the top belt is enhanced, resulting in a reduced energy and / or force transfer to the working belts and the intermediate belt. Thus, the durability of the tire can be improved and better retreading performance is achieved. Furthermore, this improved impact energy absorption also helps to eliminate tread groove cracks (for example in the centerline region of the tire) due to impacts from the road, as the impact energy is transferred to the top belt and absorbed.

[0156] It is emphasized that these aspects, embodiments or features can be combined with each other. Embodiments and / or features of one aspect can also be embodiments and / or features of another aspect.

[0157] While the present disclosure refers to an intermediate belt (for example, described as being arranged between the first and second working belts and having elongated reinforcing elements with an angle to the tire circumferential direction of less than 5°), in alternative wording, the intermediate belt can optionally be referred to herein as a small-angle belt.

[0158] The application can be susceptible to various changes and modifications, according to the description provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the application, it will be apparent to those skilled in the art that various alterations and modifications can be made thereto without departing from the scope of the application. Therefore, it is to be understood that changes can be made in the particular embodiments described, which will achieve like results and fall within the true scope of the present application, as defined by the appended claims.

Claims

1. A tire comprising a tread and a belt portion located radially below the tread, wherein the tread having two shoulder portions, each shoulder portion comprising a shoulder groove, wherein the belt portion comprises a pair of working belts and a center belt, wherein the pair of working belts comprises a first working belt and a second working belt arranged radially above the first working belt, wherein the center belt is arranged between the first working belt and the second working belt and comprises elongated reinforcing elements having an angle of less than 5° to the circumferential direction of the tire, and wherein the center belt comprises a first layer and one or more further layers, wherein the first layer of the center belt extends to cover at least 70% of the axial width of the axially largest working belt of the pair of working belts, and wherein each of the one or more further layers of the center belt is arranged radially below one of the shoulder grooves and extends to cover at most 50% of the axial width of the axially largest working belt, and wherein the belt portion further comprises a top belt layer arranged radially above the second working belt layer, wherein the top belt layer comprises a reinforcement cord having an impact energy absorption higher than 7 J / mm 2 of cord.

2. Tire according to claim 1, wherein, a second layer of the one or more further layers is arranged radially below the first shoulder groove and a third layer of the one or more further layers is arranged radially below the second shoulder groove, wherein each of the first, second and third layers is formed from a spirally wound ply strip.

3. The tire of claim 2, wherein the first, second and third layers are formed from a single ply strip.

4. The tire of claim 2, wherein the second layer is located radially below the first layer and the third layer is located radially above the first layer.

5. The tire of claim 2, wherein the second layer and the third layer are one of both located radially below the first layer and both located radially above the first layer.

6. The tire of claim 1, wherein the elongated reinforcing elements are one or more of metal cords and metal filaments.

7. The tire of claim 1, wherein the reinforcing cords of the top belt comprise steel cord having a cord structure of 5xd, where d is in the range of 0.3 to 0.5 mm.

8. The tire of claim 1, wherein the elongated reinforcing elements of the center belt are ultra-high tensile steel cord.

9. A tire comprising a tread and a belt portion located radially below the tread, wherein, the tread having two shoulder portions, each shoulder portion comprising a shoulder groove, wherein the belt portion comprises a pair of working belts and a center belt, wherein the pair of working belts comprises a first working belt and a second working belt located radially above the first working belt, wherein the center belt is arranged between the first working belt and the second working belt and comprises metal cords having i) an angle of less than 5° to the circumferential direction of the tire and ii) a cord structure according to a + b x d, where a is in the range of 1 to 5, b is in the range of 2 to 7 and d is in the range of 0.2 mm to 0.5 mm, and wherein the belt portion further comprises a top belt layer arranged radially above the second working belt layer, wherein the top belt layer comprises cords having an impact energy absorption of more than 7 J / mm 2 .

10. A tire comprising a tread and a belt portion located radially below the tread, wherein the tread has two shoulder portions, each shoulder portion comprising shoulder grooves, wherein the belt portion comprises a pair of working belts and a center belt, wherein the pair of working belts comprises a first working belt and a second working belt located radially above the first working belt, wherein the center belt is arranged between the first working belt and the second working belt and comprises elongated reinforcing elements having an angle with the circumferential direction of the tire of less than 5°, and wherein the center belt has a rubber permeability of at least 90% along at least 90% of its axial width, and wherein the center belt has a rubber permeability of at least 90% along at least 90% of its axial width, and wherein the belt portion further comprises a top belt layer, arranged radially above the second working belt layer, and the top belt layer comprises cords having an impact energy absorption rate greater than 7 J / mm 2 .

Images