FOR A NON-PNEUMATIC TIRE

FIELD OF THE INVENTION

[0001] The subject matter of the present invention relates generally to a reinforced support for a non-pneumatic tire and to a tire incorporating such support.

BACKGROUND OF THE INVENTION

[0002] The pneumatic tire is a known solution for compliance, comfort, mass, and rolling resistance. However, the pneumatic tire has disadvantages in complexity, the need for maintenance, and susceptibility to damage. A device that improves on pneumatic tire performance could, for example, provide more compliance, better control of stiffness, lower maintenance requirements, and resistance to damage.

[0003] Non-pneumatic tire or wheel constructions provide certain such improvements. The details and benefits of non-pneumatic tire or non-pneumatic wheel constructions are described in e.g., U.S. Pat. Nos. 6,769,465; 6,994,134;

7,013,939; and 7,201,194. Certain non-pneumatic tire and wheel constructions propose incorporating a resilient, annular shear band, embodiments of which are described in e.g., U.S. Pat. Nos. 6,769,465 and 7,201,194. Such non-pneumatic tire and wheel constructions provide advantages in performance without relying upon a gas inflation pressure for support of the nominal loads applied to the tire or wheel.

[0004] In some non-pneumatic constructions, vehicle load is applied to a wheel hub that is connected with an annular shear band through load bearing members in the form of e.g., multiple webs or spokes. These members can transmit the load to the annular shear band through e.g., tension, compression, or both. A layer of tread can be applied to the shear band to provide protection against the travel surface. [0005] While non-pneumatic constructions have been proposed that provide various advantages, improvements in the ability of the non-pneumatic tire to carry loads and enhance passenger comfort while reducing mass and rolling resistance are still needed.

SUMMARY OF THU INVENTION

[0006] The present invention provides a resilient composite structure for a non pneumatic tire and a tire incorporating such support structure. A continuous support membrane extends continuously along two curved, legs. A central reinforcement is positioned at a bend between the legs. The support may be connected with other components such as parts of a tire, hub, and/or other features. Additional objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

[0007] In one exemplary embodiment, the present invention provides a resilient, composite structure for connecting with components of a tire. The tire defines axial, radial, and circumferential directions. The composite structure includes a continuous support membrane forming a curved, radially-inner support leg and a curved, radially- outer support leg. The support membrane includes a bend where the radially-inner support leg and the radially-outer support leg meet. The radially-inner support leg and radially-outer support leg movable relative to each other.

[0008] A central reinforcement is connected with the continuous support membrane and positioned at the bend between the radially-outer support leg and the radially-inner support leg. The radially-outer support leg has a radially-outer end for attachment to a first component. The radially-inner support leg has a radially-inner end for attachment to a second component.

[0009] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the

specification, which makes reference to the appended figures, in which:

[0011] FIG. 1 illustrates an elevation view of an exemplary embodiment of a tire of the present invention incorporated with a cylindrically-shaped hub.

[0012] FIG. 2 illustrates a perspective and cross-sectional view of the exemplary tire of FIG. 1 taken along lines 2-2 of FIG. 1.

[0013] FIG. 3 provides is a cross-sectional view of an exemplary composite structure from FIGS. 1 and 2 as well as the exemplary tire as viewed along the axial direction.

[0014] FIG. 4 is a perspective and partial cross-sectional view of the exemplary reinforced structure of FIGS. 3 and 4 with portions of various components removed for purposes of illustration.

[0015] FIGS. 5 and 6 are side views of portions of the exemplary, reinforced structure of FIGS. 3 and 4 in compression and tension, respectively, as further described herein.

[0016] FIG.7 is a cross-sectional (along a radial plane) and perspective view of another exemplary embodiment of a tire of the present invention.

DETATEEP DESCRIPTION

[0017] For purposes of describing the invention, reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. [0018] “Axial direction” or the letter“A” in the figures refers to a direction parallel to the axis of rotation of for example, the annular band, tire, and/or wheel as it travels along a road surface.

[0019] “Radial direction” or the letter“R” in the figures refers to a direction that is orthogonal to axial direction A and extends in the same direction as any radius that extends orthogonally from the axial direction.

[0020] Circumferential direction” or the letter“C” in the figures refers to a direction is orthogonal to axial direction A and orthogonal to a radial direction R.

[0021] “Radial plane” means a plane that passes perpendicular to the equatorial plane and through the axis of rotation of the wheel.

[0022] “Elastic material” or“Elastomer” as used herein refers to a polymer exhibiting rubber-like elasticity, such as a material comprising rubber.

[0023] “Elastomeric” as used herein refers to a material comprising an elastic material or elastomer, such as a material comprising rubber.

[0024] “Deflectable” means able to be bent resiliently.

[0025] “Nominal load” or“desired design load” is a load for which the structure is designed to carry. More specifically, when used in the context of a wheel or tire, “nominal load” refers to the load for which the wheel or tire is designed to carry and operate under. The nominal load or desired design load includes loads up to and including the maximum load specified by the manufacturer and, in the case of a vehicle tire, often indicated by marking on the side of a the tire. A loading condition in excess of the nominal load may be sustained by the structure, but with the possibility of structural damage, accelerated wear, or reduced performance. A loading condition of less than nominal load, but more than an unloaded state, may be considered a nominal load, though deflections will likely be less than deflections at nominal load.

[0026] “Modulus” or“Modulus of elongation” (MPa) was measured at 10% (MA10) at a temperature of 23 °C based on ASTM Standard D412 on dumb bell test pieces. The measurements were taken in the second elongation; i.e., after an accommodation cycle. These measurements are secant moduli in MPa, based on the original cross section of the test piece. [0027] Referring now to FIG. 1, an elevation view of an exemplary embodiment of a tire 100 of the present invention as incorporated onto a hub 108 is shown. FIG. 2 is a cross-sectional view taken along a radial plane of tire 100 between resilient, composite structures 102 as indicated by line 2-2 of FIG. 1. During use, tire 100 rotates about an axis of rotation X that is parallel to axial direction A.

[0028] Tire 100 includes a plurality of the deflectable, reinforced structures 102 that are arranged adjacent to each other along circumferential direction C. Each composite structure 102 has a width W extending along axial direction A between opposing lateral sides 96 and 98. Each structure 102 is configured as a spoke-like or web-like component that, for this exemplary embodiment, extends along radial direction R between a resilient, annular band 106 and a cylindrically-shaped hub 108. The construction of each composite structure 102 is basically identical.

[0029] Tire 100 can be incorporated onto e.g., a wheel, hub, or other component positioned within or at opening O to allow tire 100 to be e.g., mounted onto an axle or other component of a vehicle so that the vehicle may roll across a ground surface. By way of non-limiting examples, such vehicle may include a passenger vehicle, heavy duty truck, light duty truck, all-terrain vehicle, bus, aircraft, agricultural vehicle, mining vehicle, bicycle, motorcycle, and others. Tire 100 may be attached to e.g., hub 108 by use of e.g., adhesives, fasteners, and combinations thereof. In still other embodiments, tire 100 and hub 108 may be integrally formed together. Other hub or wheel configurations and constructions may be used as well.

[0030] An annular tread band 110 is incorporated with resilient annular band 106. Tread band 110 may be e.g., adhered to annular band 106 or may formed integrally with annular band 106. Tread band 110 has a plurality of ribs 94 providing an outer contact surface 112 for contact with the ground or other surfaces as tire 100 rolls across. The present invention is not limited to the tread pattern shown in the figures. A variety of shapes and configurations may be used for the tread pattern of tread band 110, which may include e.g., ribs, blocks, and combinations. In other embodiments, annular band 106 may be constructed entirely from tread band 110 or integrally with tread band 110. [0031] Annular band 106 may include a plurality of reinforcing elements 114 that each extend along circumferential direction C around tire 100 within an elastomeric layer 118. For example, elastomeric layer 118 may be constructed from one or more rubber materials, polyurethanes, and combinations thereof. Reinforcing elements 114 may be e.g., cords or cables arranged along axial direction A in multiple rows 116 within layer 118.

[0032] In one exemplary embodiment, reinforcing elements 114 are“interlaced” with respect to each other along either radial direction R or axial direction A. Where reinforcing elements 114 are interlaced along axial direction A, imaginary lines extending between the center points of reinforcing elements 114 in adjacent, axially oriented rows 116 will form a rhombus or horizontal diamond having non-orthogonal angles between the sides of the rhombus. In this interlaced, horizontal diamond configuration, reinforcing elements 114 of adjacent, axially-oriented rows 116 are closer together than reinforcing elements 114 within the same axially-oriented row 116. Where reinforcing elements 114 are interlaced along radial direction R, imaginary lines extending between the center point of reinforcing elements 114 in adjacent, axially oriented rows 116 will form a rhombus or vertical diamond having non-orthogonal angles between the sides of the rhombus. In this interlaced, vertical diamond configuration, reinforcing elements 114 along the same, axially-oriented row will be closer together than reinforcing elements in non-adjacent, axially-oriented rows. As will be understood by one of skill in the art using the teachings disclosed herein, during manufacture of tire 100, a perfect positioning of reinforcing elements 114 into the shape of a vertical or horizontal diamond may not be possible due to e.g., the movement of materials during the manufacturing process. As such, slight displacements of the reinforcement elements of either diamond configuration can occur.

[0033] Reinforcing elements 114 can be constructed from a variety of materials. For example, reinforcing elements 114 can be constructed from metallic cables, or cables that are constructed from polymeric monofilaments such as PET (polyethylene terephthalate ), nylon, or combinations thereof. By way of additional example, reinforcing elements 114 could be constructed from elongate composite elements of monofilament appearance made with substantially symmetrical technical fibers, the fibers being of great lengths and impregnated in a thermoset resin having an initial modulus of extension of at least 2.3 GPa, in which the fibers are all parallel to each other. In such embodiment, the elongate composite elements will deform in an elastic manner up to a compressive strain of at least equal to 2%. As used herein, an“elastic deformation” means that the material will return approximately to its original state when the stress is released. By way of example, the fibers could be constructed from glass, certain carbon fibers of low modulus, and combinations thereof. Preferably, the thermoset resin has a glass transition temperature T _g greater than 130 °C.

Advantageously, the initial modulus of extension of the thermoset resin is at least 3 GPa. Reinforcing elements 114 could also be constructed from combinations of PET and such elongate composite elements. Additionally, reinforcing elements 114 could be constructed from hollow tubes made from rigid polymers such as e.g., PET or nylon. Other materials may be used as well.

[0034] As tire 100 rolls across e.g., a ground surface, multiple resilient structures 102 near the contact patch may flex under compression as the outer contact surface 112 passes through the contact patch. Structures 102 located elsewhere may also incur deflections but the greatest deflection of structures 102 will likely occur near the contact patch. At the same time, other resilient structures 102 located at portions along tire 100 away from the contact patch - such as e.g., opposite to the contact path - may also flex under tension.

[0035] FIG. 3 provides a cross-sectional view of the exemplary reinforced structure 102 while FIG. 4 is another perspective view of structure 102 but with portions of various components removed to reveal certain features as further described herein. For this exemplary embodiment, the cross-sectional profile in FIG.

3 is continuous along axial direction A as structure 102 extends axially over tire 100 from side 96 to opposing side 98 (FIG. 2) of tire 100.

[0036] A support membrane 104 extends continuously along radial direction R between a radially-inner end 136 and a radially-outer end 138. Support membrane 104 forms a curved, radially-inner support leg 132 and a curved, radially-outer support leg 134 and is continuous between legs 132 and 134. A bend 120 is present in support membrane 104 between support legs 132 and 134 and positioned where such legs meet. For this exemplary embodiment, bend 120 is located mid-way along the radial height H of support structure 102. In other embodiments, bend 120 may be positioned at other locations along height H.

[0037] Each support leg 132 and 134 is curved or arcuate in shape as viewed along axial direction A shown in FIG. 3. Radially-inner support leg 132 has a smooth radius of curvature RCm between bend 120 and radially inner end 136. Radially- outer support leg 134 has a smooth radius of curvature RC _I34 between bend 120 and radially-outer end 138. In one exemplary embodiment, RCm and RC have the same value and are each in the range of about 20 mm to 200 mm (20 mm < RCm £ 200 mm; 20 mm < RCm < 200 mm). For example, in one exemplary embodiment, RC 132 RC 134— 100 mm. In other embodiments, RCm arid RCm may have different values as well. Support membrane 102 has opposing sides 140 and 142 that, for this exemplary embodiment, are on opposing sides along circumferential direction C. The center of curvature C for radius of curvature RC m and the center of curvature Cm for radius of curvature RC ₁₃₄ are each along the same opposing side 142 of support membrane 104.

[0038] In an unloaded state, support membrane 104 of each spoke or resilient structure 102 forms an inclination angle a at radially-inner end 136 and radially-outer end 138. More particularly, inclination angle a ₁₃₄ (which may be positive of negative) is the angle between radial direction R and a line Tm tangent to support membrane 104 at radially-outer end 138. In one exemplary embodiment of the invention, the magnitude of the absolute value of angle a ₁₃₄ is in the range of zero degrees to 15 degrees (0 degrees < | angle am | £ 15 degrees). Similarly, inclination angle am (which may be positive of negative) is the angle between radial direction R and a line T ₁₃₂ tangent to support membrane 104 at radially-inner end 136. In one exemplary embodiment of the invention, the magnitude of the absolute value of angle a ₁₃₂ is in the range of zero degrees to 15 degrees (0 degrees < | angle a ₁₃₂ 1 < 15 degrees). For the embodiment shown in the figures, angle a ₁₃₄ and angle am are each about zero degrees (± 2 degrees) such that Tm and Tm are parallel to radial direction R. [0039] Resilient structures 102, including support membrane 104 may be constructed and reinforced in a manner that provides a desired flexural rigidity such that each may deform resiliently as structures 102 are placed under e.g., tension and compression during operation of tire 100. For example, support membrane 104 may be constructed to have a flexural rigidity of approximately 140,000 N-mm ² as measured e.g., by ASTM D709. Other values may be used as well depending upon e.g., the application.

[0040] To meet the mechanical properties required for resilient structure 102 including the appropriate flexural rigidity, different constructions may be used for support membrane 104. For the exemplary embodiment illustrated in the figures, support membrane 104 is constructed as a reinforced layer that includes a plurality of elongate reinforcements 144 (FIG. 4). Such reinforcements 144 are positioned adjacent to each other along axial direction A and extend continuously along radial direction R from radially-inner end 136 to radially-outer end 138. Reinforcements 144 may be surrounded within an elastomeric material 124 forming part of support membrane 104.

[0041] In one exemplary aspect, elongate reinforcements 144 may have a diameter of about 1 mm and may be spaced apart from each other along axial direction A at a pace of about 2 mm as measured at radially inner end 136 or radially outer end 138. Other pacings and diameters may be used as well depending upon e.g., the application for tire 100.

[0042] In certain exemplary embodiments, reinforcements 144 may be e.g., constructed from filaments formed by pultrusion of a glass reinforced resin. The filaments may have a modulus in the range of 10 GPa to 100 GPa. In still another embodiment, the filaments may have a modulus e.g., approximately 40 GPa. Other materials for construction of reinforcements 144 may be used as well including e.g., carbon fiber such as graphite epoxy, glass epoxy, aramid reinforced resins or epoxy, and combinations thereof. Fiber-reinforced plastic reinforcements 144 or metallic reinforcements 144 may also be used provided such have sufficient flexural rigidity for the nominal loads to be supported by tire 100. [0043] In still another embodiment, support membrane 104 could be constructed from a fiber reinforced plastic. For example, support membrane could be constructed as a layer of fiberglass reinforced resin where the fiberglass is formed of e.g., filaments created by pultrusion of a glass reinforced resin. The filaments may have a modulus in the range of 10 GPa to 100 GPa. In still another embodiment, the filaments may have a modulus e.g., approximately 40 GPa. Although shown as a single layer, support membrane 104 may be constructed from multiple layers as well in certain embodiments.

[0044] Each composite structure 102 also includes a central reinforcement 146. Central reinforcement 146 connects with legs 132 and 134 and is positioned between them at bend 120 in support membrane 104. Central reinforcement 146 is located on side 140 of structures 102, which is opposite of side 142 where the centers of curvature Cm and Ci ₃₄ are located.

[0045] In certain embodiments, central reinforcement 146 may provide additional support for support membrane 104. The size and material of construction for central reinforcement 146 may be selected e.g., to determine the amount of such additional support. In one exemplary embodiment, central reinforcement 146 is constructed from an elastomeric material (e.g., rubber) that extends continuously along axial direction A. In one exemplary embodiment, a rubber having a modulus in the range of 1 MPa to 10 MPa can be used. In another exemplary embodiment, a rubber having a modulus of about 4.8 MPa may be used.

[0046] Central reinforcement 146 has a thickness along radial direction R that changes along circumferential direction C. In the embodiment of tire 100 shown in FIG. 1, for example, the thickness along radial direction R of central reinforcement 146 increases along circumferential direction C moving from opposing side 142 to opposing side 140 (also referred to as central reinforcement side 140).

[0047] Each resilient structure 102 may have an opposing pair of coverings or outer layers 148, 150 made of a rubber or other elastomeric material. Outer layers 148, 150 on opposing sides 140, 142 of the support membrane 104 of each resilient structure 102. In one exemplary aspect, coverings 148, 150 may each have a modulus of approximately 5 MPa. [0048] Radially-outer end 138 can be incorporated with a first component such as resilient annular band 106 of tire 100. For example, radially-outer end 138 can be adhered (e.g., using a cyanoacrylate adhesive), bonded, mechanically connected, and/or integrally formed with annular band 106. In other embodiments, radially-outer end 138 may be incorporated with e.g., tread band 110, annular band 106, or combinations thereof. Other constructions may also be used.

[0049] Similarly, radially-inner end 136 can be incorporated with a second component such as the hub 108 of a wheel. For example, radially-inner end 136 can be adhered (e.g., using a cyanoacrylate adhesive), bonded, mechanically connected, and/or integrally formed with hub 108. By way of additional example, radially-inner end can be provided with one or more features for complementary interlocking with features of a wheel or hub of a wheel. Radially-inner end could be equipped, e.g., with dove-tail type end that fits into groove extending axially along an outer cylindrical surface of hub 108. Other constructions may be used as well.

[0050] Referring now to FIGS. 5 and 6 (elastomeric coverings 148, 150 are not shown for purposes of illustration), during operation of tire 100 as it rolls across a surface, some structures 102 may be placed in compression while other structures 102 may be placed in tension. The dashed lines of FIG. 5 illustrate a structures 102 undergoing compression while the dashed lines of FIG. 6 illustrate a structure 102 undergoing tension.

[0051] While not intending to be bound to any particular theory, the action of structures 102 during operation of tire 100 will now be described. During

compression as depicted in FIG. 5, composite structure 102 is deformed or flexed radially inward (towards the axis of rotation X). In such state, central reinforcement 146 is compressed between support legs 132 and 134. Support legs 132 and 134 may also flex and move closer together.

[0052] Conversely, during tension as depicted in FIG. 6, composite structure 102 is deformed or flexed radially outward (away from the axis of rotation X). In such state, central reinforcement 146 is in tension - pulled by support legs 132 and 134. Support legs 132 and 134 may also flex and move apart. [0053] FIG. 7 illustrates another exemplary embodiment of a tire 100 of the present invention. For this embodiment, a pair of resilient structures 102 are placed along opposing sides 96 and 98 of tire 100. Each structure 102 extends continuously along circumferential direction C. More particularly, the radially-outer support leg, 134 radially-inner support leg 132, and central reinforcement 146 of each support structure 102 extends continuously along circumferential direction C instead of axial direction A. The construction and movement of support structures 102 is otherwise as previously described.

[0054] While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments.

Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.