Reinforced resilient support for a non-pneumatic tire

Abstract

A support structure for a non-pneumatic tire and a tire incorporating such support structure. A continuous membrane extends between a radially-inner leg and a radially-outer leg. Joints and reinforcement may be provided on sides of the membrane. An annular band may be connected with the radially-outer leg. A wheel, hub, or other structure may be connected with the radially-inner leg.

Claims

1. A non-pneumatic tire defining axial, radial, and circumferential directions, the tire comprising: an annular band; a hub positioned radially inward of the annular band; a plurality of a resilient, composite structures extending between the annular band and the hub, each composite structure having opposing lateral sides along the axial direction and comprising: a continuous support membrane extending along the axial direction between the opposing lateral sides and forming a radially-inner support leg and a radially-outer support leg, the radially-outer support leg having a non-zero angle with the radially-inner support leg, the radially-inner support leg having a radially-inner end, the radially-outer support leg having a radially-outer end; a central reinforcement connected with the radially-inner support leg and the radially outer support leg; a radially-inner joint connected with the radially-inner support leg and separating the radially-inner end from the hub; a radially-outer joint connected with radially-outer support leg and incorporated with the annular band, the radially-outer joint separating the radially-outer end from the annular band; and wherein the radially-inner support leg and radially-outer support leg are movable relative to each other.

2. The non-pneumatic tire of claim 1, wherein the support membrane comprises a plurality of reinforcements.

3. The non-pneumatic of claim 2, wherein the support membrane comprises a plurality of elongate reinforcements positioned adjacent to each other along the axial direction and extending along the radial direction from the radially-inner support leg to the radially-outer support leg.

4. The non-pneumatic tire of claim 3, wherein the support membrane further comprises an elastomeric material surrounding the plurality of elongate reinforcements.

5. The non-pneumatic tire of claim 2, wherein the support membrane comprises a fiber reinforced plastic.

6. The non-pneumatic tire of claim 5, further comprising an elastomer surrounding the fiber reinforced plastic.

7. The non-pneumatic tire of claim 1, wherein the support membrane forms a radius of curvature between the radially-inner support leg and the radially-outer support leg.

8. The non-pneumatic tire of claim 1, wherein the radially-inner joint, and the radially-outer joint, each compromise an elastomeric material.

9. The non-pneumatic tire of claim 1, wherein the radially-inner joint, and the radially-outer joint, each extend continuously along an axial direction of the tire.

10. The non-pneumatic tire of claim 1, wherein the continuous support membrane defines a central reinforcement side and an opposing, leg joint side; wherein the central reinforcement is positioned on the central reinforcement side of the continuous support membrane; wherein the radially-inner joint and the radially-outer joint are positioned on the leg joint side of the continuous support membrane.

11. The non-pneumatic tire of claim 1, wherein the radially-outer joint defines a radially-outer connecting surface incorporated with an annular band of the tire.

12. The non-pneumatic tire of claim 1, wherein the radially-inner joint defines a radially-inner connecting surface incorporated with a hub of a wheel.

13. The non-pneumatic tire of claim 1, further comprising an elastomeric covering positioned onto the radially-inner support leg and the radially-outer support leg.

14. The non-pneumatic tire of claim 1, wherein the radially-outer joint defines a radially-outer connecting surface incorporated with the annular band of the tire, the annular band having a tread surface incorporated therein.

15. The non-pneumatic tire of claim 1, wherein the central reinforcement extends continuously along the axial direction between the opposing lateral sides of the composite structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1 illustrates an elevation view of an exemplary tire of the present invention incorporated onto a cylindrically-shaped hub.

(3) FIG. 2 illustrates a cross-sectional view of the exemplary tire of FIG. 1 taken along lines 2-2 of FIG. 1.

(4) FIG. 3 provides a perspective view of an exemplary, resilient structure of the present invention.

(5) FIG. 4 provides is a cross-sectional view of the exemplary structure of FIG. 3.

(6) FIG. 5 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.

(7) FIGS. 6 and 7 are side views of portions of the exemplary, reinforced structure of FIGS. 3, 4, and 5 in compression and tension, respectively, as further described herein.

DETAILED DESCRIPTION

(8) 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.

(9) “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.

(10) “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.

(11) “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.

(12) “Radial plane” or “meridian plane” means a plane that passes perpendicular to the equatorial plane and through the axis of rotation of the wheel.

(13) “Elastic material” or “Elastomer” as used herein refers to a polymer exhibiting rubber-like elasticity, such as a material comprising rubber.

(14) “Elastomeric” as used herein refers to a material comprising an elastic material or elastomer, such as a material comprising rubber.

(15) “Deflectable” means able to be bent resiliently.

(16) “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.

(17) “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.

(18) 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.

(19) 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.

(20) 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.

(21) 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 provides an outer contact surface 112 for contact with the ground or other surfaces as tire 100 rolls across. A variety of shapes and configurations may be used for tread band 100 including e.g., ribs, blocks, and combinations thereof such that the present invention is not limited to the tread shown in the figures. In other embodiments, annular band 106 may be constructed entirely from tread band 110 or integrally with tread band 110.

(22) 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.

(23) 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.

(24) 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.sub.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.

(25) Resilient annular band 106 is configured to undergo deformation as tire 100 rolls across a ground surface and portions of band 106 pass through a contact patch where outer contact surface 112 makes contact with the ground surface. Through such deformation, annular band 106 can allow outer contact surface 112 to become planar in the contact patch. Annular band 106 with e.g., reinforcement elements 114 also provides strength to support and carry a nominal load applied to tire 100 through hub 108 or other means of attachment to a vehicle. As will be further described, such nominal load may be applied to annular band 106 through compression, tension, or both, of reinforced structures 102.

(26) As tire 100 rolls across e.g., a ground surface, multiple 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.

(27) FIG. 3 provides a perspective view of a portion of an exemplary reinforced structure 102 while FIG. 4 is a cross-sectional view thereof. FIG. 5 is another perspective view of structure 102 of FIGS. 3 and 4 but with portions of various components removed to reveal certain features as further described herein. The cross-sectional profile in FIG. 4 is continuous along axial direction A as structure 102 extends axially over tire 100 from side 96 to opposing side 98.

(28) Each structure 102 includes a radially-outer joint 122 and a radially-inner joint 120. As shown, joints 120 and 122 are spaced apart from each other along radial direction R with joint 120 being radially inward of joint 122. By way of example, joint 120, 122 may each be constructed from an elastomeric material that extends continuously along axial direction A of tire 100.

(29) For this exemplary embodiment, along one side, radially-outer joint 122 includes a radially-outer connecting surface 130 that is continuous along axial direction A and has a width along circumferential direction C. Surface 130 may be slightly curved along circumferential direction C. Connecting surface 130 can be incorporated with a first component of a tire such as resilient annular band 106. For example, connecting surface 130 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 joint 122 may be incorporated with e.g., tread band 110, annular band 106, or combinations thereof. As shown in FIGS. 3 and 4, surface 130 is slightly concave along circumferential direction C for this exemplary embodiment.

(30) Similarly, along an opposing side, radially-inner joint 120 includes a radially-inner connecting surface 128. For this exemplary embodiment, connecting surface 128 is also continuous along axial direction A and has a width along circumferential direction C. Surface 128 may be slightly curved along circumferential direction C. Connecting surface 128 can be incorporated with a second component such as a hub 108 of a wheel. For example, connecting surface 128 can be adhered, bonded, mechanically connected, and/or integrally formed with hub 108. In other embodiments, radially-inner joint 120 may be incorporated with e.g., hub 108, a wheel, or combinations thereof. As shown in FIGS. 3 and 4, surface 128 is slightly convex along circumferential direction C for this exemplary embodiment.

(31) In one exemplary aspect of the invention, joint 120 and/or 122 may be connected with other components of tire 100 (e.g., with hub 108 or annular band 106) by creating such components from uncured rubber and then curing the rubber components together to form an integral construction. Similarly, in another exemplary aspect, one or more strips of green rubber could be placed between cured or partially cured components and used to cure them together.

(32) In another exemplary aspect of the invention, joints 120 and 122 are constructed from a relatively soft rubber. In one exemplary embodiment, a rubber having a modulus in the range of 1 MPa to 10 MPa may be used. In still another exemplary embodiment, a rubber having a modulus of about 4.8 MPa may be used.

(33) Each resilient structure 102 has a pair of support legs 132 and 134. Radially-inner support leg 132 has a radially-inner end 136 to which radially-inner joint 120 is connected. Radially-outer support leg 134 has a radially-outer end 138 to which radially-outer joint 122 is connected. Along the length of radially-inner support leg 132, radially-inner joint 120 is spaced apart and discrete from a central reinforcement 148. Similarly, along the length of radially-outer support leg 134, radially-outer joint 122 is spaced apart and discrete from central reinforcement 148. For this exemplary embodiment, radially-outer support leg 134 may connected with annular band 106 by radially-outer joint 122. Radially-inner support leg 132 may be connected with hub 108 by radially-inner joint 120.

(34) In certain embodiments, radially-inner support leg 132 may be slightly different in length than radially-outer support leg 134. More particularly, leg 132 may be shorter than leg 134 or vice-versa. Having e.g., radially-inner support leg 132 shorter than radially-outer support leg 134 may be utilized to better accommodate changes in radius as portions of structures 102 are affected by the passage of contact surface 112 through the contact patch. For example, such difference in length may facilitate adjacent structures 102 “nesting” or deforming together as each structure 102 pass through the contact patch when tire 100 rolls across a surface (particularly when overloaded).

(35) Legs 132, 134 form a non-zero angle α that is less than 180 degrees when tire 100 is not loaded. Legs 132, 134 form a central reinforcement side 140 (same side as angle α) and an opposing leg joint side 142 of each resilient structure 102. Radially-inner leg 132 extends between central reinforcement 148 and a radially-inner end 136 at joint 120. Radially-outer leg 134 extends between central reinforcement 148 and radially-outer end 138 at joint 122.

(36) Continuing with FIGS. 3, 4, and 5, a support membrane 104 extends continuously between radially-inner support leg 132 and radially-outer support leg 134. By way of example, support membrane 104 may be constructed from a plurality of reinforcements within e.g., rubber or another elastomeric material. For this exemplary embodiment, support membrane 104 includes a plurality of elongate, reinforcements 144 surrounded by a rubber material 164 (FIG. 5). Reinforcements 144 and rubber material 164 extends continuously between legs 132 and 134.

(37) Support membrane 104 has a smooth radius of curvature SM.sub.RC (FIG. 4) between radially-inner support leg 132 and radially-outer support leg 134 at knee 151 of support 102. The magnitude for radius of curvature SM.sub.RC will depend on e.g., the overall size of tire 100, the height along radial direction R of each support 102, and other variables.

(38) Reinforcements 144 are adjacent to one another along axial direction A and extend along radial direction R between radially-outer end 138 of radially-outer support leg 134 and radially-inner end 136 of radially-inner support leg 132. In one exemplary aspect, as depicted in FIG. 4, a portion of support membrane 104 including reinforcements 144 within leg 132 are substantially within a first plane. Similarly, another portion of membrane 104 including reinforcements 144 within leg 134 are substantially within a second plane that is at a non-zero angle to the first plane. Near radially-inner end 136, support membrane 104 may have a slight radius of curvature providing a concave shape on side 140. Near radially-outer end 138, support membrane 104 may have a slight radius of curvature providing a concave shape on side 140.

(39) 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.

(40) 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.

(41) In still another embodiment, support membrane 104 could be constructed as 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.

(42) Other constructions may also be used for resilient structures 102, including membrane 104 of support legs 132 and 134. Resilient structures 102 are constructed and reinforced in a manner that allows flexural rigidity such that each may deform resiliently as structures 102 are placed under tension and compression during operation of tire 100. For example, support legs 132 and 134 may have a flexural rigidity of approximately 140,000 N-mm.sup.2 as measured e.g., by ASTM D709. Other values may be used as well depending upon e.g., the application for tire 100.

(43) Radially-outer end 138 of support leg 134 is attached to radially-outer joint 122 and is allowed to compress or stretch radially-outer joint 122 during operation of tire 100. Similarly, radially-inner end 136 of support leg 132 is attached to radially-inner joint 120 and is allowed to compress or stretch radially-inner joint 120 during operation of tire 100.

(44) Each composite structure 102 also includes central reinforcement 148. Central reinforcement 148 connects with legs 132 and 134 and is positioned between them at a bend in support membrane 104. Central reinforcement 148 is located on central reinforcement side 140 of structures 102 whereas joints 120, 122 are located on the opposing (along circumferential direction C) leg joint side 142.

(45) In certain embodiments, central reinforcement 148 may provide additional support for support membrane 104. The size and material of construction for central reinforcement 148 may be selected e.g., to determine the amount of such additional support. In one exemplary embodiment, central reinforcement 148 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. Central reinforcement 148 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 148 increases along circumferential direction C moving from leg joint side 142 to central reinforcement side 140.

(46) Each resilient structure 102 may have a covering or outer layer 152 made of a rubber or other elastomeric material. Outer layer 152 may be placed on both sides 140, 142 of structures 102. In one exemplary aspect, each covering 152 may have a modulus of approximately 5 MPa.

(47) Referring now to FIGS. 6 and 7 (elastomeric covering 152 is 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. 6 illustrate a structures 102 undergoing compression while the dashed lines of FIG. 7 illustrate a structure 102 undergoing tension.

(48) 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. 6, structure 102 is deformed or flexed radially inward (towards the axis of rotation X). In such state, central reinforcement 148 is compressed between support legs 132 and 134. At the same time, radially-outer joint 122 undergoes highest compression along a portion nearest central reinforcement 148 and undergoes lowest compression or undergoes tension on an opposing portion farthest from central reinforcement 148. Similarly, during compression, radially-inner joint 120 undergoes compression along a portion nearest central reinforcement 148 and undergoes tension on an opposing portion farthest from central reinforcement 148.

(49) Conversely, during tension as depicted in FIG. 7, structures 102 are deformed or flexed radially outward (away from the axis of rotation X). In such state, central reinforcement 148 is in tension—pulled by support legs 132 and 134. At the same time, radially-outer joint 122 undergoes highest tension along a portion nearest central reinforcement 148 and undergoes lowest tension or compression on an opposing portion farthest from central reinforcement 148. Similarly, during tension, radially-inner joint 120 undergoes highest tension along a portion nearest central reinforcement 148 and undergoes lowest tension or compression on an opposing portion farthest from central reinforcement 148.

(50) For the embodiment shown, support membrane 104 of each support structure 102 is not connected directly to hub 108 or annular band 106. During compression (FIG. 6), the distance along radial direction R between radially-inner end 136 and 138 can decrease as legs 132 and 134 move closer together. During tension (FIG. 7), the distance along radial direction R between radially-inner end 136 and 138 can increase as legs 132 and 134 move apart. In each such case, central reinforcement 148 can also act somewhat like a hinge so that the angle α between portions of legs 132 and 134 may change as tire 100 rolls across a surface and support legs 132 and 134 rotate into, and out of, proximity to the contact patch.

(51) 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.