BACKGROUND

Field

[0001] Embodiments relate generally to pneumatic tires, and more specifically, to tires having a belt construction.

Description of the Related Art

[0002] Pneumatic tires generally include a tire carcass and a belt arranged around the tire carcass. Commonly, the belt is formed of multiple stacked belt layers, each of which being a reinforcement layer including a plurality of spaced-apart, elongate metal reinforcements. As a result, the summit of a tire having multiple stacked metal belt layers is heavy and inflexible. Also, because the elongate metal reinforcements extend substantially in a circumferential direction of the belt or tire (that is, approximately 0 degrees relative to the circumferential direction of the tire), to provide the necessary circumferential or hoop strength of the belt and tire, this greatly prevents the belt from stretching or expanding during tire construction operations. For example, this reduced ability to expand can make molding operations difficult. Additionally, because the belt does not substantially expand, the belt is commonly assembled separate from the tire carcass, and later, after belt assembly, applied to the tire carcass to form an assembled, uncured tire. Accordingly, there is a need to overcome these issues.

SUMMARY

[0003] Embodiments include a pneumatic tire. Particular embodiments include a cured pneumatic tire with a tire carcass having one or more body ply reinforcement layers. The one or more body ply reinforcement layers extend along each of a pair of sidewalls and between a pair of beads where the beads are spaced apart in an axial direction of a tire. An annular belt extends around a radial extent of the tire carcass. The annular belt has a width and a single primary reinforcement layer extending around the tire and across the width of the belt. The annular belt also has an annular belt cap layer. The annular belt cap layer extends around a radial outer extent of the primary reinforcement layer. The annular belt cap layer has a width which extends at least across the width of the belt and includes one or more cap reinforcement layers. Each of the one or more cap reinforcement layers extend around the tire. [0004] The single primary reinforcement layer includes a plurality of elongate metal reinforcements. The elongate metal reinforcements are spaced apart at least partially along a length of the annular belt and have a metal reinforcement length extending at least partially in a direction of the annular belt width where the metal reinforcement length for each of the elongate metal reinforcements extends in a direction biased from an equatorial plane of the tire by an angle of 70 degrees to 90 degrees in absolute value.

[0005] Each of the one or more cap reinforcement layers include a plurality of elongate non-metal reinforcements. The elongate non-metal reinforcements are spaced apart at least partially along the length of the annular belt and have a non-metal reinforcement length extending at least partially in the direction of the annular belt width and where the non-metal reinforcements extend in the direction biased from the equatorial plane of the tire by an angle of 0 degrees to 10 degrees in absolute value.

[0006] Various embodiments may have an elastomeric separation layer positioned between the single primary reinforcement layer and the annular belt cap layer. In some of these embodiments, the elastomeric separation layer may have a thickness of up to 3 mm.

[0007] Some embodiments also include an intermediate reinforcement layer arranged between the single primary reinforcement layer and the annular belt cap layer. The intermediate reinforcement layer includes a plurality of elongate reinforcements spaced apart at least partially along the length of the annular belt and each have a reinforcement length extending at least partially in the direction of the annular belt width where the reinforcement length for each of the elongate reinforcements extends in the direction biased from the equatorial plane of the tire by an angle of 70 degrees to 90 degrees in absolute value. The intermediate reinforcement layer has a width extending partially across the width of the single primary reinforcement layer.

[0008] Additional embodiments are described below.

DETAILED DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a front sectional view of a tire, in accordance with a particular embodiment.

[0010] FIG. 2 is an exploded view of a belt of the tire of FIG. 1.

[0011] FIG. 3 is a partial top view of the belt of the tire of FIG. 2.

[0012] FIG. 4 is an exploded view of a belt of a tire, in accordance with another embodiment.

[0013] FIG. 5 is an exploded view of a belt of a tire, in accordance with a further embodiment.

[0014] FIG. 6 is a partial top view of a belt of the tire of FIG. 5.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0015] Embodiments described herein include pneumatic tires having a belt with a single primary reinforcement layer extending around the tire. The single primary reinforcement layer extends across a width of the belt and includes a plurality of spaced-apart elongate metal reinforcements. This single primary reinforcement layer may also be referred to as a single, metal-reinforced belt layer. The elongate metal reinforcements in this single primary reinforcement layer are biased by an angle of +/- 70 degrees to +/- 90 degrees, or 70 to 90 degrees, in absolute value, relative to the circumferential direction of the tire, or, stated differently, relative to an equatorial plane of the belt or tire. The belt also includes a cap layer, the cap layer being a reinforcement layer formed of non-metal elongate reinforcements and extending substantially across the width of the belt. In some embodiments the cap layer may extend across the full width of the belt. The non-metal elongate reinforcements extend lengthwise in a direction biased by an angle of 0 degrees to +/- 10 degrees from the circumferential direction of the tire or belt or from an equatorial plane of the belt or tire. Additional details and other variations are described herein.

[0016] Commonly, tires have a plurality of belt layers each formed of elongate metal reinforcements, where each of these metal-reinforced belt layers extend the substantial width of the belt or the substantial effective rolling width of the tire tread. As noted previously, when multiple metal-reinforced belt layers are used, and especially when the metal reinforcements in each layer extend in the circumferential direction of the belt or tire (that is, unbiased to an equatorial plane of the belt or tire), the belt is restricted from stretching or expanding during tire construction and molding operations. And while the metal-reinforced belt layers are provided at the summit to provide sufficient strength to resist breaking energy, use of multiple metal-reinforced belt layers greatly increase the weight of a tire and reduce the flexibility of the tire. Accordingly, embodiments described herein, incorporating a single primary reinforcement layer, provide various benefits, including significantly reducing the mass and weight of the tire and the overall rolling resistance. As a result, these belts may be employed by lightweight vehicles. [0017] A tire as described herein is a pneumatic tire, and includes a tire carcass having one or more body ply reinforcement layers extending along each of a pair of side walls and between a pair of beads spaced apart in an axial direction of a tire. It is appreciated that the tire carcass may comprise any tire carcass formed of any construction as desired by one of ordinary skill in the art.

[0018] The tire also includes an annular belt having a length extending circumferentially around a radial extent of the tire carcass, and a width extending laterally generally in an axial direction of the tire. As noted previously, the belt includes the single primary reinforcement layer having a plurality of spaced-apart metal elongate reinforcements. The single primary reinforcement layer extends around the tire and across the width of the belt. The elongate metal reinforcements are spaced apart, and each has a length, also referred to as a "metal reinforcement length," extending at least partially in the direction of the annular belt width. In particular embodiments, the length for each elongate metal reinforcement extends in a direction biased from the circumferential direction of the tire, or, stated differently, from an equatorial plane of the tire, by an angle of +/- 70 degrees to +/- 90 degrees, or, in other words, 70 to 90 degrees, in absolute value.

[0019] The belt also includes an annular belt cap layer extending circumferentially around a radial extent of the tire carcass. The annular belt cap layer has a width extending across a width of the belt. The annular belt cap layer is formed of one or more cap reinforcement layers, each of the one or more cap reinforcement layers extending circumferentially around the tire. Each of the one or more cap reinforcement layers includes a plurality of elongate non-metal reinforcements. The plurality of elongate non-metal reinforcements are spaced apart in a direction generally perpendicular to a length of each metal reinforcement. The length of each elongate non-metal reinforcement, which is also referred to as a "non-metal reinforcement length," extends at least partially in the circumferential direction of the tire. In certain embodiments, the length of each of elongate non-metal reinforcement extends in a direction biased from the circumferential direction, or from an equatorial plane of the tire, by an angle of 0 degrees to +/- 10 degrees, or, in other words, 0 to 10 degrees in absolute value. In particular embodiments, the annular belt cap layer is formed of a single cap reinforcement layer extending at least substantially across the width of the belt. At least substantially across the width of the belt means that the cap reinforcement layer extends at least 90% of the belt width, but may extend the full belt width or may even extend beyond the full belt width. In other variations, the annular belt cap layer is formed of a plurality of cap reinforcement layers, which are stacked in a radial direction of the tire. It is appreciated that each of the plurality of cap reinforcement layers may extend partially or at least substantially across the width of the belt.

[0020] It is appreciated that any reinforcement layer discussed herein may be provided in any form known to one of ordinary skill. For example, any reinforcement layer may be provided having the plurality of elongate reinforcements (whether metal or non- metal) arranged within an elastomeric polymer matrix. The elastomeric polymer may form any desired natural or synthetic rubber. Metal reinforcements are constructed from chords most commonly formed of steel, but may be formed of any metal. Non-metal reinforcements are constructed from chords formed of any fabric or textile, such as polyester, rayon, nylon, aramid, silk, or fiberglass. The chords may be formed of a plurality of the wire (metal) or yarn/filaments (non-metal, arranged lengthwise and twisted along their lengths, as desired). In one particular embodiment, the non-metal reinforcements within the annular belt cap layer are aramid. In another particular embodiment, the non-metal enforcements within the annular belt cap layer are silk. In yet another embodiment, multiple annular belt cap layers having non-metal reinforcements may be provided, including the same or different materials in each respective layer to reach a sufficient strength and to maintain the desired mass. It is appreciated embodiments may comprise any combination of materials forming the chords.

[0021] Optionally, in certain embodiments, one or more intermediate elastomeric layers of a desired thickness may be arranged between the single primary reinforcement layer and the annular belt cap layer. The one or more intermediate elastomeric layers form an elastomeric separating layer between the single primary reinforcement layer and the annular belt cap layer. In particular embodiments, one of the one or more intermediate elastomeric layers has a thickness of up to 3 mm. It is appreciated that each of the intermediate elastomeric layers may be formed of any elastomeric material, including any desired natural or synthetic rubber.

[0022] Embodiments may also include an intermediate reinforcement layer. The intermediate reinforcement layer is arranged between the single primary reinforcement layer and the annular belt cap layer and extends annularly around the tire. The intermediate reinforcement layer includes a plurality of spaced apart elongate reinforcements, each elongate reinforcement having a length (a "reinforcement length") extending in a direction biased from the circumferential direction of the tire, or, in other words, from the equatorial plane of the tire, by an angle of +/- 70 degrees to +/- 90 degrees (that is, 70 to 90 degrees in absolute value). The intermediate reinforcement layer also has a width extending partially across the width of the single belt reinforcement layer. In certain instances, the width of the intermediate reinforcement layer is equal to 10 percent (10%) to 20 percent (20%) of the belt width or of the single primary reinforcement layer width. It is also appreciated that the width of the intermediate reinforcement layer is arranged to extend along the widthwise centerline of the belt or tire, whether or not the intermediate reinforcement layer is centered across the belt or tire width. It is also appreciated that the plurality of reinforcements arranged within the intermediate reinforcement layer may comprise any metal or non-metal reinforcement, or a combination thereof. In a particular embodiment, the intermediate reinforcement layer is formed of aramid. In another particular embodiment, the intermediate reinforcement layer is formed of metal. It is understood that more than one intermediate reinforcement layer may be provided.

[0023] In particular embodiments, the reinforcement length for each of the elongate reinforcements in the intermediate reinforcement layer extends at an angle of -70 degrees to - 90 degrees and the reinforcement length for each of the elongate reinforcements in the single belt reinforcement layer extends at an angle of 70 degrees to 90 degrees in the direction bias the equatorial plane of the tire, or vice versa. In other words, the reinforcement length of the elongate reinforcements of the intermediate reinforcement layer cross the reinforcement length for each of the elongate reinforcements in the single belt reinforcement layer, at an equatorial plane of the tire. Thereby, a mesh configuration is formed between the two layers.

[0024] When a tire includes the optional elastomeric separation layer together with the optional one or more intermediate reinforcement layers, any one or all of the one or more intermediate reinforcement layers may be separated from either the annular belt cap and/or the single primary reinforcement layer (or more generally the belt) by the elastomeric separation layer or by any of the one or more intermediate polymer layers.

[0025] In particular embodiments, the single primary reinforcement layer, the belt cap layer, and any intermediate reinforcement layer are arranged along a central portion of the tire carcass between the pair of beads. The single primary reinforcement layer, the belt cap layer, and any intermediate reinforcement layer, if included, are stacked in a radial direction. In one particular embodiment, the single primary reinforcement layer is stacked radially inward or below the belt cap layer. In yet another embodiment, the single primary reinforcement layer is stacked radially inward or below the annular belt cap layer with an intermediate reinforcement layer between the single primary reinforcement layer and the belt cap layer. [0026] The single belt reinforcement layer, the belt cap layer, and the intermediate reinforcement layer each have a width formed relative a rolling tread width. The rolling tread width is the width of the tire tread that is available for engagement with a ground surface during tire operation. In particular embodiments, the single belt layer width is 80 percent (80%) to 90 percent (90%) of the rolling tread width and, when present, the intermediate reinforcement layer width is 8 percent (8%) to 18 percent (18%) of the rolling tread width. It is appreciated that the widths of the different layers may be defined with reference to one another. For example, in certain embodiments, the intermediate reinforcement layer width is 10 percent (10%) to 20 percent (20%) of the width of the single belt layer. In combination with the corresponding width, each respective width may be further defined by a minimum dimension. For example, in particular embodiments, the intermediate reinforcement layer width is 10 percent (10%) to 20 percent (20%) of the width of the single belt layer and a minimum of 25 mm.

[0027] It is appreciated that in certain embodiments, the single belt reinforcement layer width, the belt cap layer width, and the intermediate reinforcement layer width, when present, are symmetrical about the an equatorial plane of the tire (that is, the widthwise centerline of the tire). However, in other embodiments, one or more layer widths may be offset relative the equatorial plane of the tire. This may include offsetting one or more layers, or a combination of layers, in a balanced or unbalanced configuration.

[0028] The embodiments of the tires discussed above will now be discussed below in association with particular embodiments shown in the figures.

[0029] With reference to FIG. 1, a cross-sectional view of a cured, pneumatic tire 10 is shown in accordance with a particular embodiment. It is noted that tire 10 includes a rotational axis A defining an axial direction of the tire. A radial direction R is also identified, which extends perpendicular to rotational axis A and the axial direction. Tire 10 includes a tread 12 arranged overtop a belt 20 comprising a single primary reinforcement layer 30 and an annular belt cap layer 40, all of which are bonded to a tire carcass 15. In this particular embodiment, the annular belt cap layer 40 is radially outward of the single primary reinforcement layer 30. In other words, the single primary reinforcement layer 30 is radially inward of the annular belt cap layer 40. Tire 10, and carcass 15, include a pair of sidewalls 14 spaced apart in the axial direction A of the tire, one or more body ply reinforcement layers 16 extending along each of the sidewalls and between a pair of beads 18 spaced apart in the axial direction A of the tire. The axial direction also identifies a direction of the tire width, as well as a direction of the belt width, the primary reinforcement layer width W30, and the cap width W40. A widthwise centerline CL is shown defining an equator extending around a perimeter of the tire 10. An equatorial plane EP extends through the tire 10 along the centerline CL. FIG. 2 is a close-up view of the tire shown in FIG. 1.

[0030] FIG. 3 is a top cutaway view of the belt 20 of FIGs. 1-2, showing the single primary reinforcement layer 30 and the annular belt cap layer 40. Each layer forms a sheet and includes a plurality of elongate reinforcements formed within an elastomeric polymer matrix 22. The single primary reinforcement layer 30 includes elongate metal reinforcements 32 and the annular belt cap layer 40 includes elongate non-metal reinforcements 42. The elongate metal reinforcements 32 of the single primary reinforcement layer 30 extend lengthwise in a direction biased by an angle θι from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative to the equatorial plane EP. The angle θι is +/- 70 degrees to +/- 90 degrees from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative to the equatorial plane EP. The elongate non-metal reinforcements 42 of the annular belt cap layer 40 extend lengthwise in a direction biased by an angle Θ2 from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative the equatorial plane EP. The angle Θ2 is 0 degrees to +/- 10 degrees from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative to the equatorial plane EP.

[0031] With reference to FIGs. 1-3, the widths of the single primary reinforcement layer 30 and/or the annular belt cap layer 40 may each be expressed as a percentage in a direction of a full belt width or a rolling tread width W12. In particular embodiments, the rolling tread width W12 can be effectively referred to as a width or a tread arc which engages the operating surface (not shown). The rolling tread width W12 is defined to extend between locations P arranged on opposing sides of centerline CL along the tread width. In particular embodiments, the single primary reinforcement layer width W30 may be a portion of the rolling tread width W12. By example, the single primary reinforcement layer may be equal to or less than 85 percent (85%) of the rolling tread width W12.

[0032] With reference to FIG. 4, an exploded view of another embodiment of a belt 20 is illustrated. In this embodiment, the belt 20 includes an elastomeric separation layer 60. The elastomeric separation layer 60 is positioned between a single primary reinforcement layer 30 and an annular belt cap layer 40. The elastomeric separation layer 60 may be formed separately in the elastomeric polymer matrix 22. In one particular embodiment, the elastomeric separation layer 60 is 3 mm.

[0033] With reference to FIG. 5, yet another embodiment of a belt 20 is provided. In this embodiment, the belt 20 includes an intermediate reinforcement layer 50. The intermediate reinforcement layer 50 is arranged between a single primary reinforcement layer 30 and an annular belt cap layer 40. The intermediate reinforcement layer 50 has an intermediate reinforcement layer width W50 and comprises elongate reinforcement 52.

[0034] FIG. 6 is a top cutaway view of the belt 20 of FIG. 5, showing the single primary reinforcement layer 30, the intermediate reinforcement layer 50, and the annular belt cap layer 40. Each belt layer forms a sheet and includes a plurality of the respective reinforcements formed within an elastomeric polymer matrix 22. The single belt reinforcement layer 30 includes elongate metal reinforcements 32 and the annular belt cap layer 40 includes elongate non-metal reinforcements 42. The intermediate reinforcement layer 50 may comprise elongate metal reinforcements and/or elongate non-metal reinforcements. The elongate reinforcements 52 of the intermediate reinforcement layer 50 extend lengthwise in a direction biased by an angle Θ3 from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative to the equatorial plane EP. The angle Θ3 is +/- 70 degrees to +/- 90 degrees from the circumferential direction of the tire or belt or from the widthwise centerline CL of the tire or belt or relative to the equatorial plane EP. In this particular embodiment, the elongate reinforcements 52 in the intermediate reinforcement layer 50 extend lengthwise in a direction biased by an angle Θ3 that is -70 degrees to -90 degrees and the elongate reinforcements 42 in the single belt reinforcement layer 30 extend lengthwise in a direction biased by an angle θι that is 70 degrees to 90 degrees. In yet another embodiment, the elongate reinforcements in the intermediate reinforcement layer and the elongate reinforcements in the single belt reinforcement layer may be oriented vice versa. In contrast, the angle Θ2 of the elongate reinforcements 42 of the annular belt cap layer 40 extend lengthwise in a direction biased by an angle of 0 degrees to +/- 10 degrees.

[0035] To the extent used, the terms "comprising," "including," and "having," or any variation thereof, as used in the claims and/or specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms "a," "an," and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The terms "at least one" and "one or more" are used interchangeably. The term "single" shall be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as "two," are used when a specific number of things is intended. The terms "preferably," "preferred," "prefer," "optionally," "may," and similar terms are used to indicate that an item, condition or step being referred to is an optional (i.e., not required) feature of the embodiments. Ranges that are described as being "between a and b" are inclusive of the values for "a" and "b" unless otherwise specified.

[0036] While various improvements have been described herein with reference to particular embodiments thereof, it shall be understood that such description is by way of illustration only and should not be construed as limiting the scope of any claimed invention. Accordingly, the scope and content of any claimed invention is to be defined only by the terms of the following claims, in the present form or as amended during prosecution or pursued in any continuation application. Furthermore, it is understood that the features of any specific embodiment discussed herein may be combined with one or more features of any one or more embodiments otherwise discussed or contemplated herein unless otherwise stated.