Non-pneumatic tire with carbon fiber band

Abstract

A non-pneumatic tire includes a lower ring, an upper ring coaxial with the lower ring, support structure extending from the lower ring to the upper ring, and a circumferential tread extending about the upper ring. The circumferential tread includes a band layer constructed of a fiber composite material. The fiber composite material includes a plurality of ply layers that are arranged into a ply lay-up. The ply lay-up has an asymmetric construction.

Description

NON-PNEUMATIC TIRE WITH CARBON FIBER BANDFIELD OF INVENTION

[0001] The present disclosure relates to non-pneumatic tires, and a method of making the same. More particularly, the present disclosure relates to a nonpneumatic tire that includes a tire tread with a carbon fiber band layer attached to a tread rubber layer, and a method of making the same.BACKGROUND

[0002] Various tire constructions have been developed that enable a tire to run in an uninflated or underinflated condition. Non-pneumatic tires do not require inflation, while “run flat tires" may continue to operate after receiving a puncture that causes a complete or partial loss of pressurized air, for extended periods of time and at relatively high speeds. Non-pneumatic tires may include a plurality of spokes, a webbing, or other support structure that connects a lower ring to an upper ring. In some non-pneumatic tires, a circumferential tread may be wrapped about the upper ring of the tire.

[0003] The circumferential tread may contain a shear element having an elastic region disposed between upper and lower inelastic regions. The shear element may also be referred to as a band layer, shear band, a tread band, or a thin annular high strength band element. When used in a pneumatic tire, the shear element acts as a tension member when the tire is pressurized. When used in a non-pneumatic tire, or a pneumatic tire in an unpressurized or partially pressurized state, the shear element acts as a structural compression member.

[0004] Tire design, for both pneumatic and non-pneumatic tires, involves balancing many factors including, but not limited to, impact resistance, handling, speed rating, load capacity, and ride quality. Regardless of the balance that is selected between the various design factors, non-pneumatic tires must be durable enough to withstand high impact events (e.g., striking a curb, pothole, or other obstruction or road imperfection). It is known to manufacture certain components of a tire out of steel, which may provide the desired durability. The use of steel.however, may result in a heavy tire, which may negatively affect vehicle performance.SUMMARY OF THE INVENTION

[0005] In one embodiment, a non-pneumatic tire includes a lower ring, an upper ring coaxial with the lower ring, support structure extending from the lower ring to the upper ring, and a circumferential tread extending about the upper ring. The circumferential tread includes a band layer constructed of a fiber composite material. The fiber composite material includes a plurality of ply layers that are arranged into a ply lay-up. The ply lay-up has an asymmetric construction.

[0006] In another embodiment, a method of manufacturing a non-pneumatic tire includes the steps of providing a lower ring, an upper ring, support structure, and a circumferential tread. The upper ring is arranged to be coaxial with the lower ring. The lower ring and the upper ring are connected with the support structure. The circumferential tread is attached about the upper ring. Providing the circumferential tread includes manufacturing the circumferential tread with a band layer constructed of a fiber composite material. The fiber composite material includes a plurality of ply layers that are arranged into a ply lay-up. The ply lay-up has an asymmetric construction.

[0007] In yet another embodiment, a band layer for a tire includes a plurality of ply layers that are arranged into a ply lay-up. The ply lay-up has an asymmetric, balanced, homogeneous construction.BRIEF DESCRIPTION OF DRAWINGS

[0008] In the accompanying drawings, structures are illustrated that, together with the detailed description provided below, describe exemplary embodiments of the claimed invention. Like elements are identified with the same reference numerals. It should be understood that elements shown as a single component may be replaced with multiple components, and elements shown as multiple components may be replaced with a single component. The drawings are not to scale, and the proportion of certain elements may be exaggerated for the purpose of illustration.

[0009] Figure l is a side view of an undeformed non-pneumatic tire,0

[0010] Figure 2 is a side view of the non-pneumatic tire of Figure 1 being deformed when subjected to a load,

[0011] Figure 3 is a sectional view along 3-3 of Figure 1,

[0012] Figure 4 is a detailed cross-sectional view of an exemplary ply lay-up for a band layer.

[0013] Figure 5 is a schematized partial plan view of one ply layer of the exemplary' ply lay-up of Figure 4,

[0014] Figure 6 is a schematized partial plan view of another ply layer of the exemplary ply lay-up layer of Figure 4,

[0015] Figure 7a is a table identifying the fiber material orientation for ply layers in a symmetrical ply lay-up,

[0016] Figure 7b is a table identifying the fiber material orientation for ply layers in an asymmetrical ply lay-up,

[0017] Figure 8a is a table identifying the fiber material orientation for ply layers in a balanced ply lay-up,

[0018] Figure 8b is a table identifying the fiber material orientation for ply layers in a balanced ply lay-up,

[0019] Figure 8c is a table identifying the fiber material orientation for ply layers in an unbalanced ply lay-up,

[0020] Figure 8d is a table identifying the fiber material orientation for ply layers in an unbalanced ply lay-up,

[0021] Figure 9a is a table identifying the fiber material orientation for plie ply layers s in a homogenous ply lay-up,

[0022] Figure 9b is a table identifying the fiber material orientation for ply layers in a homogenous ply lay-up,

[0023] Figure 9c is a table identifying the fiber material orientation for ply layers in a heterogenous ply lay-up.

[0024] Figure 9d is a table identifying the fiber material orientation for ply layers in a heterogenous ply lay-up,

[0025] Figure 10 is a detailed cross-sectional view of an exemplary ply lay-up that may be used to construct a band layer that may make up part of the nonpneumatic tire of Figure 1,

[0026] Figure 11 is a table identifying the fiber material orientation of an exemplary ply lay-up that can be used for the band layer of Figure 10.

[0027] Figure 12 is a schematized partial plan view of one ply layer of the exemplary' ply lay-up of Figure 10,

[0028] Figure 13 is a schematized partial plan view of another ply layer of the exemplary ply lay-up of Figure 10. and

[0029] Figure 14 is a table identifying the fiber material orientation of another exemplary' ply lay-up that can be used for the band layer of Figure 10.DETAILED DESCRIPTION OF THE INVENTION

[0030] The following includes definitions of selected terms employed herein. The definitions include various examples or forms of components that fall within the scope of a term and that may be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of terms may be within the definitions.

[0031] “Axial’’ and “axially” refer to a direction that is parallel to the axis of rotation of a tire.

[0032] “Circumferential” and “circumferentially” refer to a direction extending along the perimeter of the surface of the tread perpendicular to the axial direction.

[0033] “Radial” and “radially” refer to a direction perpendicular to the axis of rotation of a tire.

[0034] “Tread” as used herein, refers to that portion of the tire that comes into contact with the road or ground under normal load.

[0035] While similar terms used in the following descriptions describe common tire components, it should be understood that because the terms carry slightly different connotations, one of ordinary' skill in the art would not consider any one of the following terms to be purely interchangeable with another term used to describe a common tire component.

[0036] Directions are stated herein with reference to the axis of rotation of the tire. The terms “upward” and “upwardly” refer to a general direction towards the tread of the tire, whereas "downward" and "downwardly" refer to the general direction towards the axis of rotation of the tire. Thus, when relative directional terms such as “upper” and “lower” or “top” and “bottom” are used in connection with an element, the “upper” or “top” element is spaced closer to the tread than the “lower” or “bottom” element. Additionally, when relative directional terms such as “above” or “below” are used in connection with an element, an element that is “above” another element is closer to the tread than the other element.

[0037] The terms “inward” and “inwardly” refer to a general direction towards the equatorial plane of the tire, whereas “outward” and “outwardly” refer to a general direction aw ay from the equatorial plane of the tire and tow ards the side of the tire. Thus, when relative directional terms such as “inner” and “outer” are used in connection with an element, the “inner” element is spaced closer to the equatorial plane of the tire than the “outer” element.

[0038] Figures 1-3 illustrate one embodiment of anon-pneumatic tire 10. The non-pneumatic tire 10 is merely an exemplary' illustration and is not intended to be limiting. In the illustrated embodiment, the non-pneumatic tire 10 includes a generally annular lower ring 20 that may engage a wheel (not shown) on which the tire 10 is mounted. The lower ring 20 has a bottom surface 23 and a top surface 24 and may be made of an elastomeric material or metal. In alternative embodiments, the lower ring may be indirectly connected to a wheel. In other alternative embodiments, the lower ring may be made of any desired material.

[0039] The non-pneumatic tire 10 further includes a generally annular upper ring 30. The upper ring 30 may be configured to deform in an area 48 around and including a footprint region 32 (see Figure 2), which may decrease vibration and increase ride comfort.

[0040] The upper ring 30 has a bottom surface 33 and a top surface 34 and may be made of an elastomeric material or metal. In alternative embodiments, the upper ring may be made of any desired material.

[0041] Support structure 40 extends between the top surface 24 of the lower ring 20 and the bottom surface 33 of the upper ring 30 to interconnect the upper ring 30 and the lower ring 20. The support structure 40 may be made of an elastomeric material or metal. In the illustrated embodiment, the support structure 40 is an interconnected web having at least two radially adjacent layers 56, 58 of web elements 42, 44 that define a plurality of generally polygonal openings 50.

[0042] In alternative embodiments, the support structure may be made of any desired material. In other alternative embodiments, the support structure may have any desired configuration, such as spokes. The spokes may be linear, curvilinear, or any desired shape (e.g., V-shaped or serpentine shaped). In other alternative embodiments, the non-pneumatic tire may include spokes of two or more different shapes. For example, the non-pneumatic tire may include C-shaped spokes that alternate with V-shaped spokes along a circumferential direction of the non- pneumatic tire. In still yet other alternative embodiments, the spokes may extend in a non-radial direction of the non-pneumatic tire.

[0043] A circumferential tread 70 is attached to the top surface 34 of the upper ring 30. The circumferential tread 70 includes a band layer 140 and a tread layer 150 on which a tread pattern may be formed. The band layer 140 may bend to assist in carrying a load on the non-pneumatic tire 10.

[0044] The band layer 140 may be manufactured out of a fiber composite material. As understood by those of ordinary skill in the art. a ‘Tiber composite material” may by a material that includes fibers bound by resin. Before further describing the construction of the band layer 140, it may be helpful to discuss terminology used herein to describe attributes of fiber composite materials.

[0045] As understood by those of ordinary' skill in the art, a structure manufactured of fiber composite material may include one or more discrete layers. Each layer may also be referred to as a “ply layer.” Immediately adjacent ply layers form a “ply pair.” A structure may be formed out of a plurality of ply layers, which are collectively referred to as a “ply lay-up.”

[0046] For the purposes of this explanatory discussion, consider an exemplary' ply lay-up 500 as shown in Figures 4-6. This exemplary ply lay-up 500 includes12 ply layers 505a...1. Each ply layer includes fiber material 510 bound in a resin 515. Six ply layers 505a... f are located above a midplane M and six ply layers 505g...1 are located below the midplane M. As used herein, “midplane” refers to a plane that is centrally located between a top surface and a bottom surface of the ply lay-up 500 along a radial direction R of the non-pneumatic tire. The first and second ply layers 505a, 505b form a first ply pair 520a, the third and fourth ply layers 505c, 505d form a second ply pair 520b, and so on until the eleventh and twelfth ply layers 505k, 5051, which form the sixth ply pair 520f. Each ply layer 505a...1 has a thickness T that extends in the radial direction R of the nonpneumatic tire and a width W that extends in the axial direction A of the nonpneumatic tire.

[0047] Among other characteristics, each ply layer 505a...1 may be defined with reference to the orientation of the fiber material 510 contained therein. For the purposes of this disclosure, the orientation of the fibers will be made with reference to the circumferential direction C of the non-pneumatic tire.

[0048] A ply layer with a 0° fiber material orientation means that the fiber material extends parallel with the circumferential direction of the non-pneumatic tire, and a ply layer with a 90° fiber material orientation means that the fiber material extends perpendicular to the circumferential direction (i.e., in the axial direction) of the non-pneumatic tire.

[0049] A ply layer with a positive degree fiber material orientation (e.g., +5°, +10°, etc.) has fiber material extends that forms the specified positive degree angle with respect to the circumferential direction of the non-pneumatic tire as measured in a clockwise direction CW. An exemplary positive degree fiber material orientation ply layer 505 is shown in Figure 5, with the fiber material 510 forming a positive angle with respect to the circumferential direction C of the non-pneumatic tire.

[0050] A ply layer with a negative degree fiber material orientation (e.g., -5°, - 10°, etc.) has fiber material that forms the specified negative degree angle with respect to the circumferential direction of the non-pneumatic tire as measured in a counterclockwise direction CCW An exemplar}’ negative degree ply layer 505 isshown in Figure 6, with the fiber material 510 forming a negative angle with respect to the circumferential direction C of the non-pneumatic tire.

[0051] The overall makeup of a ply lay-up may be defined using the following terms: (1) symmetry, (2) balance, and (3) homogeneity. These terms are not meant to be an exhaustive list of terms that may be used to define the overall makeup of a ply lay-up.

[0052] “Symmetry” considers whether ply layers located an equal distance from the midplane M on opposite sides of the midplane M of the ply-lay up along the radial direction R of the non-pneumatic tire are identical. As used herein “identical” ply layers means the ply layers have identical fiber material orientation, identical fiber material (including dimensions), and identical resin material.

[0053] Considering symmetry with respect to the ply lay-up 500 shown in Figure 4 involves comparing the sixth and seventh ply layers 505f, 505g, the fifth and eighth ply layers 505e. 505h, the fourth and ninth ply layers 505d, 505i, the third and tenth ply layers 505c, 505j, the second and eleventh ply layers 505b, 505k, and the first and twelfth ply layers 505a, 5051. It is assumed that each one of these ply layers 505a...1 has the same fiber material and the same resin material.

[0054] Table 1 as shown in Figure 7a identifies a symmetric ply lay-up while Table 2 as shown in Figure 7b identifies an asymmetric ply lay-up. In Tables 1 and 2 (as well as Tables 3-13, discussed below), each ply layer is identified as “Ply n,” where n refers to the particular ply layer. Table 1 in Figure 7a identifies a symmetric ply lay-up 500 because the groups consisting of the sixth and seventh ply layers 505f, 505g, the fifth and eighth ply layers 505e, 505h, the fourth and ninth ply layers 505d, 505i, the third and tenth ply layers 505c, 505j, the second and eleventh ply layers 505b, 505k, and the first and twelfth ply layers 505a, 5051 each have an identical fiber material orientation. Table 2 in Figure 7b identifies an asymmetric ply lay-up 500 because the group consisting of the sixth and seventh ply layers 505f, 505g do not have an identical fiber material orientation despite the fact that the remaining groups of ply layers do have an identical fiber material orientation. In this example, although only a single ply layer group consisting of the sixth and seventh ply layers 505f, 505g is not identical, this still results in theply lay-up being asymmetric. It is understood that the ply lay-up would also be asymmetric if any other one of the enumerated groups of ply layers were not identical or if multiple groups of ply layers were not identical.

[0055] "Balance" considers whether there are an equal number of positive degree fiber material orientation ply layers and negative degree fiber material orientation ply layers throughout the ply lay-up. Balance does not take into consideration the location of the ply layers with respect to the midplane M or the distribution of the ply layers throughout the ply lay-up. Balance does, however, take into account the magnitude of the fiber material orientation. In other words, a ply lay-up is balanced if the sum of the orientations of all of the ply layers is 0°.

[0056] Table 3 as shown in Figure 8a identifies a balanced ply lay-up 500 because it has six +5° ply layers 505a, 505c, 505e, 505g, 505i, 505k and six -5° ply layers 505b, 5050, 505f, 505h, 505j, 5051 distributed throughout the ply lay-up 500. In this example, the positive degree fiber material orientation ply layers 505a, 505c, 505e, 505g, 505i, 505k and the negative degree fiber material orientation ply layers 505b, 505d, 505f, 505h, 505j, 5051 are distributed equally on opposite sides of the midplane M. Table 4 as shown in Figure 8b also identifies a balanced ply lay-up. In this example, the positive degree fiber material orientation ply layers 505a...d, 505g, 505h and the negative degree fiber material orientation ply layers 505e, 505f, 505i...1 are not distributed equally on opposite sides of the midplane M. with four positive degree fiber material orientation ply layers 505a... d and two negative degree fiber material orientation ply layers 505e, 505f above the midplane M and two positive degree fiber material orientation ply layers 505g, 505h and four negative degree fiber material orientation ply layers 505i...1 below the midplane M. Despite this, Table 4 in Figure 8b is still a balanced ply lay-up because through the entirety of the ply lay-up 500 there are six positive degree fiber material orientation ply layers 505a... d. 505g, 505h and six negative degree fiber material orientation ply layers 505e, 505f, 505i...1. Furthermore, although two of the ply layers have a six degree fiber material orientation 505f, 505h, Table 4 in Figure 8b is still a balanced ply lay-up 500 because the ply lay-up 500 has both a positive six degree fiber material orientation ply layer 505h and a negative six degree fiber materialorientation ply layer 505f. As discussed above, balance only takes into consideration whether there are an equal number of positive degree fiber material orientation ply layers and negative degree fiber material orientation ply layers throughout the ply lay-up (including considering magnitude of the fiber material orientation) but does not consider the location of the ply layers.

[0057] Table 6 as shown in Figure 8c identifies an unbalanced ply lay-up 500 because it has five +5° ply layers 505a, 505c, 505e, 505i, 505k and seven -5° ply layers 505b, 505d, 505f...h, 505j, 5051 distributed throughout the ply lay-up 500. Thus, this ply lay-up 500 does not have an equal number of positive degree fiber material orientation ply layers and negative degree fiber material orientation ply layers. Table 7 as shown in Figure 8d also identifies an unbalanced ply lay-up 500. In this example, there are six positive degree fiber material orientation ply layers 505a, 505c, 505e, 505g, 505i, 505k and six negative degree fiber material orientation ply layers 505b. 505d, 505f, 505h, 505j, 505k. Despite this. Table 7 in Figure 8d is still an unbalanced ply lay-up 500 because the magnitude of the positive degree fiber material orientation ply layers 505a, 505c, 505e, 505g, 505i, 505k and the negative degree fiber material orientation ply layers 505b, 505d, 505f, 505h, 505j, 505k is not the same. For example, the first ply layer 505a has a +10° fiber material orientation but there are no corresponding -10° fiber material orientation ply layers in the ply lay-up 500. As another example, the tenth ply layer 505j has a -6° fiber material orientation but there are no corresponding +6° fiber material orientation ply layers in the ply lay-up 500. Here, the sum of the orientations of all of the ply layers is +9°.

[0058] “Homogeneity” considers whether the various ply layer fiber material orientations that make up the ply lay-up are evenly distributed. A ply lay-up is heterogeneous if there is a preferential stacking of specific ply layer fiber material orientations anywhere in the ply lay-up. In other words, a ply lay-up is heterogenous if two or more immediately adjacent ply layers have the same fiber material orientation. As an example, if a 12 ply lay-up is composed of two different fiber material orientations — A, B — an example of a heterogeneous ply lay-up would be [A, A, B, A, B, B, B, A, A, B, A, B], As another example, if a 12 ply lay-up is composed of three different fiber material orientations — A, B, C — an example of a heterogeneous ply lay-up would be [A, B, C, C, A, B, C, C, A, A, A, B], In both of these examples, at least two adjacent ply layers have the same fiber material orientation and are therefore heterogeneous.

[0059] A ply lay-up is homogeneous if the various ply layer fiber material orientations that make up the ply lay-up are evenly distributed. Tn other words, a ply lay-up is homogeneous if the various ply layer fiber material orientations are stacked to form a repeatable pattern. As an example, if a 12 ply lay-up is composed of two different fiber material orientations — A. B — an example of a homogeneous ply lay-up is [A, B, A, B, A, B, A, B, A, B, A, B], As another example, if a 12 ply lay-up is composed of three different fiber material orientations — A, B, C — an example of a homogeneous ply lay-up is [A, B, C, A, B, C, A, B, C, A, B, C], In both of these examples, the ply layer fiber material orientations form a repeatable pattern (i.e.. are evenly distributed throughout the ply lay-up).

[0060] Tables 8-11, as shown in Figures 9a-9d, respectively, are identify specific examples of homogeneous and heterogeneous ply lay-ups. Table 8 in Figure 9a identifies a ply lay-up 500 with a repeating pattern of +5° ply layers 505a, 505c. 505e 505g, 505i, 505k and -5° ply layers 505b, 505d, 505f. 505h, 505j, 505k. This ply lay-up 500 is homogeneous because it has a pattern that repeats throughout the ply lay-up 500 and the ply layer fiber material orientations are therefore evenly distributed. Table 9 in Figure 9b identifies a ply lay-up 500 with a repeating pattern of +5° ply layers 505a. 505c, 505e. 505g, 505i, 505k and - 3° ply layers 505b, 505d, 505f. 505h, 505j, 505k. Although the magnitude of the positive degree fiber material orientation ply layers 505a, 505c, 505e. 505g, 505i, 505k is different than the magnitude of the negative degree fiber material orientation ply layers 505b, 505d, 505f. 505h, 505j, 505k, the ply lay-up 500 is still homogeneous because the ply layer fiber material orientations are evenly distributed.

[0061] Table 10 in Figure 9c identifies a heterogeneous ply lay-up 500. This lay-up is heterogeneous because it has several instances where at least two adjacent ply layers have the same fiber material orientation. In particular, the first throughthird ply layers 505a...c share the same fiber material orientation, the fifth and sixth ply layers 505e, 505f share the same fiber material orientation, and the ninth through eleventh ply layers 505i...k share the same fiber material orientation. The aforementioned groups of ply layers have a preferential stacking of the respective shared fiber material orientation, which results in the ply lay-up 500 being heterogeneous. Table 1 1 in Figure 9d also identifies a heterogeneous ply lay-up 500. This ply lay-up 500 only has two adjacent ply layers — the seventh and eighth ply layers 505g, 505h — that share the same fiber material orientation. This, however, is enough to create preferential stacking of a specific ply layer fiber material orientation, which results in the ply lay-up 500 being heterogeneous.

[0062] Figures 10-13 show an exemplary embodiment of a ply lay-up 600 for the band layer 140 of the non-pneumatic tire 100 shown in Figures 1-3. The ply lay-up 600 includes ply layers 605a... t, 607a... t of a fiber composite material that includes a fiber material 610 and a resin 615 that binds the strands of fiber material 610. According to one example embodiment, the fiber material 610 is carbon fiber and the resin 615 is epoxy. In alternative embodiments, the fiber material or the resin may be any desired material. For example, the fiber material may be fibers made up of glass, aramid, boron, alumina, silicon carbide, quartz, or ultrahigh molecular weight polyethylene. As another example, if the fiber material includes carbon, the carbon may be produced with three precursor materials including rayon, polyacrylonitrile, and isotropic, liquid crystalline pitches. As yet another example, the resin may be of the thermoset or the thermoplastic type. Examples of thermoset resins that may be used include, but are not necessarily limited to, epoxy, phenolformaldehyde, resoles, novolacs, bismaleimide, or polyimides. Examples of thermoplastic resins that may be used include, but are not necessarily limited to polyethylene, polypropylene, polyamides, polyphenylene sulfide, polyarylketone, polysulfone, polyamide-imide, polyphenylsulfone, polyphenylene sulfide, or silicone.

[0063] In the illustrated embodiment, the ply lay-up 600 includes 40 ply layers 605a...t, 607a...t, with 20 ply layers 605a...j, 607a...j being located above a midplane M and 20 ply layers 605k.. ,t. 607k...t being located below the midplaneM. The first ply layer 605a is the top ply (i.e. , ply that is closest to the tread layer 150 and furthest from the lower ring 20 along the radial direction R of the nonpneumatic tire 10). The second ply layer 607a is located below the first ply layer 605a, the third ply layer 605b is located below the second ply layer 607a, and so on until the fortieth ply layer 607t, which is the bottom ply layer (i.e., ply layer that is closest to the upper ring 30 and furthest from the tread layer 150 along the radial direction R of the non-pneumatic tire 10).

[0064] In alternative embodiments, the ply lay-up may include a greater or fewer number of ply layers. Preferably, the ply lay-up 600 12-80 ply layers. More preferably, the ply lay-up 600 includes 20-60 ply layers. Even more preferably, the ply lay-up 600 includes 32-48 ply layers.

[0065] In other alternative embodiments, the ply layers may not be equally divided on opposite sides of the midplane of the ply lay-up. In still other alternative embodiments, the number of ply layers may be such that all the ply layers may not be part of a pair. For example, a band layer having 41 ply layers would result in one of the ply layers not being part of a ply pair.

[0066] The fiber material 610 that makes up the ply layers 605a... t, 607a... t has a substantially circular cross section with a diameter of 0.00754 inches (0. 1915 mm). In alternative embodiments, the fiber material may have any desired diameter or may have a cross section that is any desired shape. According to one example, the fiber material preferably has a diameter of 0.00752-0.00757 inches (0.1910- 0. 1922 mm). As understood by those of ordinary skill in the art, the diameter of the fiber material may be larger or smaller depending on the material.

[0067] Each ply layer has a thickness T that extends in the radial direction R of the non-pneumatic tire 10 and a width W that extends in an axial A direction of the non-pneumatic tire 10. The ply layer thickness T is substantially same as the diameter of the fiber material. The ply layer width is a function of the design of the non-pneumatic tire, and those of ordinary skill in the art understand that some applications prefer or require a relatively wider tire while other applications prefer or require a relatively narrower tire. In alternative embodiments, the ply lay-up may include a mix of ply layers having different dimensions.

[0068] The entire ply lay-up has a width Wpithat is substantially equal to a width Wbi of the band layer 140. In alternative embodiments, the band layer may be made up of a multi-part ply lay-up. For example, as indicated by the broken lines in Figure 10, the ply lay-up that makes up the band layer 140 may be made up of three separate, discrete ply lay-ups 600a. 600b, 600c that are secured to one another. In alternative embodiments, there may be a greater or fewer number of separate discrete ply lay-ups that are secured to one another.

[0069] Table 12 in Figure 11 identifies an exemplary ply layer fiber material orientation for the ply lay-up of Figure 10. According to this example, the odd number ply layers 605a...t (i.e. , the first, third, fifth, seventh, etc.) have a -2° fiber material orientation and the even number ply layers 607a...t (i.e., the second, fourth, sixth, eighth, etc.) have a +2° fiber material orientation. An exemplar}' ply layer 607 having a +2° fiber material orientation is schematically shown in Figure 12 and an exemplar}' ply layer 605 having a -2° fiber material orientation is schematically shown in Figure 13. Table 13 in Figure 14 identifies another exemplar ' ply layer fiber material orientation for the ply lay-up of Figure 10. According to this example, the odd number ply layers 605a... t have a +2° fiber material orientation and the even number ply layers 607a...t (i.e., the second, fourth, sixth, eighth, etc.) have a -2° fiber material orientation. In alternative embodiments, the ply layers may have fiber material orientation in the range of + / - 0-40, more preferably in the range of + / - 0-20, and even more preferably in the range of + / - 2-40.

[0070] Thus, both of the exemplary ply lay-ups 600 are asymmetric, balanced, homogeneous lay-ups. The exemplary ply lay-ups 600 are asymmetric because ply layers located an equal distance from the midplane M on opposite sides of the midplane M of the ply lay-up are not identical. Rather, in both ply lay-ups 600 the respective ply layers have opposite degree fiber material orientations, with one of the ply layers having a positive degree fiber material orientation and a respective one other of the ply layers having a negative degree fiber material orientation. The exemplary ply lay-ups 600 are balanced because there are an equal number of positive degree fiber material orientation ply layers and negative degree fibermaterial orientation ply layers throughout the ply lay-up 600. In particular, both ply lay-ups 600 have 20 positive degree fiber material orientation ply layers and 20 negative degree fiber material orientation ply layers and all the ply layers have a 2° magnitude. Thus, the sum of the orientations of all of the ply layers is 0°. The exemplary ply lay-ups 600 are homogeneous because the ply layer fiber material orientations that make up the ply lay-up 600 are evenly distributed. In particular, in both ply lay-ups 600 the +2° fiber material orientation ply layers and -2° fiber material orientation ply layers alternate with one another through the ply lay-up and there are no instances of two or more immediately adjacent ply layers having the same fiber material orientation.

[0071] It has been found that providing an asymmetric ply lay-up for the band layer 140 unexpectedly improves the performance of the band layer 140. Conventional composite material manufacturing techniques discourage the use of asymmetric lay-ups because asymmetric lay-ups may create shear / extension couplings and result in warpage during manufacturing (i.e., dimensional stability problems). The inventors have found, however, that using an asymmetric ply layup reduces bend / twist coupling. In the context of the purpose and function of the band layer 140, reducing bend / twist coupling decreases bending stress thereby resulting in a more robust band layer 140, which ultimately improves nonpneumatic tire 10 performance.

[0072] Design parameters of the ply lay-up 600 may be selected in order to “‘tune" the band layer 140 to provide desired non-pneumatic tire 10 performance. For example, increasing the number of ply layers may decrease free rolling stresses, decrease lateral deflection of the non-pneumatic tire, increase stresses during high impact events, and increase band layer stiffness, which increases vertical stiffness of the non-pneumatic tire. Decreasing the number of ply layers may increase free rolling stresses, increase lateral deflection of the non-pneumatic tire, decrease stresses during high impact events, and decrease band layer stiffness, which decreases vertical stiffness of the non-pneumatic tire.

[0073] While the band layer and tread rubber layer have been described with respect to non-pneumatic tires, it should be understood that they may also be employed in pneumatic tires.

[0074] To the extent that the term ‘‘includes'’ or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Gamer, A Dictionary of Modem Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” Furthermore, to the extent the term “connect” is used in the specification or claims, it is intended to mean not only “directly connected to,” but also “indirectly connected to” such as connected through another component or components.

[0075] While the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the application, in its broader aspects, is not limited to the specific details, the representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant’s general inventive concept.

Claims

CLAIMSWhat is claimed is:

1. A non-pneumatic tire comprising: a lower ring; an upper ring coaxial with the lower ring; support structure extending from the lower ring to the upper ring; and a circumferential tread extending about the upper ring, the circumferential tread including a band layer constructed of a fiber composite material, the fiber composite material including a plurality of ply layers that are arranged into a ply lay-up, the ply lay-up having an asymmetric construction.

2. The non-pneumatic tire of claim 1, wherein the ply lay-up has a balanced construction.

3. The non-pneumatic tire of claim 1, wherein the ply lay-up has a homogeneous construction.

4. The non-pneumatic tire of claim 1, wherein the ply lay-up includes between 12- 80 ply layers.

5. The non-pneumatic tire of claim 1, wherein one of an even numbered ply layers of the plurality of ply layers and an odd numbered ply layers of the plurality of ply layers has a fiber material orientation in the range of 0 - +40°.

6. The non-pneumatic tire of claim 5, wherein one other of the even numbered ply layers of the plurality of ply layers and the odd numbered ply layers of the plurality of ply layers has a fiber material orientation in the range of 0 - -40°.

7. The non-pneumatic tire of claim of claim 1, wherein a top ply layer has a negative fiber material orientation.

8. The non-pneumatic tire of claim 1, wherein a top ply layer has a positive fiber material orientation.

9. The non-pneumatic tire of claim 1, wherein the fiber composite material includes fibers bound by resin, the fiber being at least one of carbon, glass, aramid, boron, alumina, silicon carbide, quartz, or ultrahigh molecular weight polyethylene.

10. The non-pneumatic tire of claim 1, wherein the fiber composite material includes fibers bound by resin, the resin being at least one of epoxy, polyester. phenol-formaldehyde, resoles, novolacs, bismaleimide, polyimides, polyethylene, polypropylene, polyamides, polyphenylene sulfide, polyarylketone, polysulfone, polyamide-imide. polyphenylsulfone, polyphenylene sulfide, or silicone.

11. A method of manufacturing anon-pneumatic tire comprising the steps of: providing a lower ring, an upper ring, support structure, and a circumferential tread; arranging the upper ring to be coaxial with the lower ring; connecting the lower ring and the upper ring with the support structure; and attaching the circumferential tread about the upper ring; wherein the step of providing the circumferential tread includes manufacturing the circumferential tread with a band layer constructed of a fiber composite material, the fiber composite material including a plurality of ply layers that are arranged into a ply lay-up. the ply lay-up having an asymmetric construction.

12. The method of manufacturing a non-pneumatic tire according to claim 11, wherein the ply lay-up has a balanced construction.

13. The method of manufacturing a non-pneumatic tire according to claim 11, wherein the ply lay-up has a homogeneous construction.

14. The method of manufacturing a non-pneumatic tire according to claim 11, wherein the ply lay-up includes between 12-80 ply layers.

15. The method of manufacturing a non-pneumatic tire according to claim 11, wherein one of an even numbered ply layers of the plurality of ply layers and an odd numbered ply layers of the plurality of ply layers has a fiber material orientation in the range of 0 - +40°, and wherein one other of the even numbered ply layers of the plurality of ply layers and the odd numbered ply layers of the plurality of ply layers has a fiber material orientation in the range of 0 - -40°.

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