METHOD OF FORMING NON-PNEUMATIC TIRE USING INTERMEDIATE SECTION

FIELD OF THE INVENTION

[0001] The present invention relates generally to a method of constructing a non-pneumatic tire from a series of subsections. More particularly, the present application involves a method of constructing a non-pneumatic tire with multiple shear band layers and at least one intermediate section.

BACKGROUND

[0002] Non-pneumatic tires for vehicles and other applications are known that may include a hub surrounded circumferentially by an outward radially disposed tread that includes an annular shear band ring. A supporting structure that may have a series of spokes can be disposed radially between the hub and shear band ring and can function to connect these two components. As the tire rotates under load, the spokes experience bending, extension and compression deformation when they are located downward near the contact patch of the tire. The spokes straighten outside the contact patch relieving the bending and compression deformation.

[0003] The formation of the non-pneumatic tire may involve the insertion of the shear band ring into a mold and then overmolding the supporting structure onto the interior of the shear band ring through injection molding. However, this will generate a large amount of pressure onto the shear band ring causing distortion and damage thereto. Further, injection molding of the supporting structure across the entire axial length of the non-pneumatic tire may be difficult in that material will not easily flow along the entire axial length during this process. Further, thin mold sections between features of the supporting structure, such as spokes, may be damaged by pressure variations in the manufacturing process.

[0004] Another method of formation involves the formation of the supporting structure and then subsequent attachment to the shear band ring. Attachment through adhesives requires precise control of critical parameters such as temperature, humidity, coating thickness, application pressure, and clamping time. Further, such attachment requires very precise and expensive fixtures to properly locate features of the supporting structure, such as spokes, with respect to the shear band ring. Still further, the use of adhesives in the manufacturing process may cause fouling of the tooling and equipment by the adhesive itself. As such, there remains room for variation and improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] 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 more particularly in the remainder of the specification, which makes reference to the appended Figs, in which:

[0006] Fig. 1 is a perspective view of a non-pneumatic tire.

[0007] Fig. 2 is a perspective exploded assembly view of a non-pneumatic tire composed of a hub and a series of intermediate sections inserted into an outer shear band ring.

[0008] Fig. 3 is a perspective view of an outer shear band ring.

[0009] Fig. 4 is a perspective view of a series of inner shear band rings.

[0010] Fig. 5 is a side elevation view of an intermediate section formed by molding a supporting structure into an inner shear band ring.

[0011] Fig. 6 is a side elevation view of an intermediate section assembled into an outer shear band ring.

[0012] Fig. 7 is a front view of a non-pneumatic tire made of a series of intermediate sections inserted into an outer shear band ring.

[0013] Fig. 8 is a side elevation view of a non-pneumatic tire with a hub assembled into the inner V pair spoke section of the intermediate section.

[0014] Fig. 9 is a partial perspective cross-sectional view of a non-pneumatic tire with the outer shear band ring disassembled from the inner shear band ring.

[0015] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention. DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

[0016] Reference will now 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, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.

[0017] It is to be understood that the ranges mentioned herein include all ranges located within the prescribed range. As such, all ranges mentioned herein include all sub-ranges included in the mentioned ranges. For instance, a range from 100-200 also includes ranges from 110-150, 170- 190, and 153-162. Further, all limits mentioned herein include all other limits included in the mentioned limits. For instance, a limit of up to 7 also includes a limit of up to 5, up to 3, and up to 4.5.

[0018] The present invention provides for a method of forming a non-pneumatic tire 10 that includes a hub 20, a supporting structure 16, and a shear band ring 56. The method involves the construction of a plurality of intermediate sections 14 that each have an inner shear band ring 18. These intermediate sections 14 may be assembled into an outer shear band ring 12, and a hub 20 may be subsequently attached to complete the assembly. The intermediate sections 14 may be made up of a supporting structure 16 that includes an inner V pair spoke section 40, an interface ring 42, and an outer V pair spoke section 44.

[0019] With reference to Fig. 1, a non-pneumatic tire 10 is shown through which a central axis 58 extends. The central axis 58 is identified with other components of the non-pneumatic tire 10 and relates to the position of these components once assembled into the non-pneumatic tire 10. An axial direction 24 is defined as the direction along the central axis 58 or the direction parallel to the central axis 58. The radial direction 22 of the non-pneumatic tire 10 extends at a 90 degree angle to the axial direction 24, and the circumferential direction 26 extends around the arc length of the non-pneumatic tire 10 so as to circle 360 degrees the central axis 58. As with the axial direction 24, the radial direction 22 and the circumferential direction 26 are identified with other components in the drawings that are then subsequently assembled into the non-pneumatic tire 10 as their orientations would be upon assembly. The non-pneumatic tire 10 includes a hub 20 that can be mounted onto a wheel of the vehicle. The central axis 58 extends through the center of the hub 20.

[0020] Located outward from the hub 20 in the radial direction 22 is a supporting structure 16. The supporting structure 16 may be designed in a variety of manners. As shown, the supporting structure 16 includes an inner V pair spoke section 40, an interface ring 42, and an outer V pair spoke section 44. The spokes are V shaped with apexes that are oriented to and are located at one another between the inner and outer V pair spoke sections 40 and 44. However, it is to be understood that the supporting structure 16 can be provided in a variety of manners and need not include V shaped spokes, and need not include an inner and outer section in other embodiments. Instead, the supporting structure 16 may include simply a plurality of spokes that are linear in shape and that are arranged completely around the supporting structure 16 in the circumferential direction 26. As such, it is to be understood that the configuration of the supporting structure 16 illustrated and described is only exemplary and that other arrangements are possible in other configurations of the non-pneumatic tire 10 and method disclosed herein.

[0021] The non-pneumatic tire 10 also has a shear band ring 56 that engages the supporting structure 16 and is located radially outward from the supporting structure 16 in the radial direction 22. Tread 60 is also included in the non-pneumatic tire 10 and is attached to the shear band ring 56. The supporting structure 16 may be formed as a single component, or can be made by individually constructing two or three subcomponents and then assembling these two or three modular pieces together to form the supporting structure 16. Construction in two or three modular pieces may allow for benefits in cost and performance to be realized.

[0022] An exploded perspective view of a non-pneumatic tire 10 is shown in Fig. 2. The tire 10 includes a plurality of intermediate sections 14, 28 and 34 that can all be formed in the same manner with the same components. The intermediate sections include supporting structures 16, 30 and 36 that are located inward in the radial direction 22 from corresponding inner shear band rings 18, 32 and 38. The intermediate sections 14, 28 and 34 are positioned into an outer shear band ring 12 so as to lie against one another in the axial direction 24. The shear band ring 56 is thus made up of an outer shear band ring 12 and a number of inner shear band rings 18, 32 and 38 and is not formed as a single component. The various spokes of the supporting structures 16, 30, and 36 do not directly engage the outer shear band ring 12 but are instead offset therefrom by the inner shear band rings 18, 32 and 38. A hub 20 is located within and is attached to the intermediate sections 14, 28 and 34.

[0023] The method for forming the non-pneumatic tire 10 may first involve the building and curing of the outer shear band ring 12 and the inner shear band rings 18, 32 and 38. The outer shear band ring 12 is shown in Fig. 3, and three inner shear band rings 18, 32 and 38 are shown in Fig. 4. The number of inner shear band rings 18, 32 and 38 may vary depending upon the width of the outer shear band ring 12 which is the length of the outer shear band ring 12 in the axial direction 24. Any number of inner shear band rings 18, 32 and 38 may be utilized and they may or may not be sized the same in the axial direction 24. The number and size of the inner shear band rings 18, 32 and 38 may be dependent upon molding constraints of other features of the non-pneumatic tire 10 such as the spokes. The outer shear band ring 12 may include any number of layers of the resulting shear band ring 56. Likewise, the inner shear band rings 18, 32 and 38 can include any number of layers of the resulting shear band ring 56. In some embodiments, the inner shear band rings 18, 32 and 38 include two layers of the shear band ring 56. The inner shear band rings 18, 32 and 38 are portions of the shear band ring 56 and are not portions of the spokes and are not rings of the supporting structures, 16, 30 and 36 in that they can include the same materials as other portions of the shear band ring 56 such as the outer shear band ring 12. The number of layers and the thickness in the radial direction 22 of the inner shear band rings 18, 32 and 38 can be selected so that the inner shear band rings 18, 32 and 38 can be arranged in such as way so that they can be inserted into the outer shear band ring 12 when the intermediate sections 14, 28 and 34 are inserted.

[0024] The next step in the assembly process may be the formation of the intermediate section 14. Once the inner shear band ring 18 is formed, it may be placed as an insert within a mold for the formation of the supporting structure 16. The mold into which the inner shear band ring 18 may be placed can be an injection mold. With reference to Fig. 5, the supporting structure 16 may include an inner V pair spoke section 40, an interface ring 42, and an outer V pair spoke section 44. These sections 40, 42 and 44 can be injection molded and upon their formation by injection molding the outer V pair spoke section 44 can bond directly to the inner surface 52 of the inner shear band ring 18. This type of process is known as overmolding in the injection molding process. The mold that includes the components of the supporting structure 16 such as the inner V pair spoke section 40, interface ring 42, and the outer V pair spoke section 44 may control the precision of location of the attachment of the spokes of the outer V pair spoke section 44 to the inner shear band ring 18 and may eliminate the challenges associated with attaching the spokes to the shearband 56. Such an attachment also minimizes the amount of material needed for attachment of the spokes to the shearband 56. Although described as using injection molding, any type of molding may be used to create/attach components of the non-pneumatic tire 10 such as the inner shear band ring 18, the supporting structure 16, or the inner shear band ring 18

[0025] The inner surface 52 of the inner shear band ring 18 may be prepared by a plasma treatment or a chemical treatment. The inner surface 52 may be primed by being chemically prepared either by plasma or chemical adhesion promoter. This priming may be done before the injection molding in order to help the outer V pair spoke section 44 better adhere to the inner surface 52 of the inner shear band ring 18. Alternatively, the inner shear band ring 18 may be primed by the application of cushion gum instead of the use of plasma or chemical adhesion treatment. The cushion gum can have a chemistry tailored for adhesion with the particular outer V pair spoke section 44 material or compound being used.

[0026] The components of the supporting structure 16 such as the inner V pair spoke section 40, interface ring 42, and outer V pair spoke section 44 can be made out of thermoplastic elastomers such as thermoplastic urethanes, polyether block amides, copolyester ethers, polyolefin elastomers, and plastomers. In some embodiments, other materials may be used to construct the inner V pair spoke section 40, interface ring 42, and outer V pair spoke section 44 could be more rigid thermoplastic materials such as polyethylene, polypropylene, and nylon. In some embodiments, the supporting structure 16 and the other described components may be made out of a polymeric material such as polyurethane, copolyester, polyether block amide, or polyolefins.

[0027] The second intermediate section 28 may be constructed in a similar manner as the first intermediate section 14 as previously discussed. In this regard, the components of the second supporting structure 30 such as the outer V pair spoke section of the second supporting structure 30 may be molded onto the inner surface of the second inner shear band ring 32 through an

overmolding in the injection molding process. The third intermediate section 34 may likewise be constructed as in a similar manner as the first intermediate section 14 previously discussed.

Components of the third supporting structure 36 such as the outer V pair spoke section can be molded onto the inner surface of the third inner shear band ring 38. The inner surfaces of the second and third inner shear band rings 32 and 38 may be prepped in the same manners as the inner surface 52, and the materials making up the second and third intermediate sections 28 and 34 may be the same as the intermediate section 14 as previously discussed and a repeat of this information is not necessary. If additional intermediate sections are needed in other embodiments, they may be provided as previously discussed with respect to the first intermediate section 14.

[0028] The next step in the assembly process after the construction of the number of intermediate sections 14, 28 and 34 needed is the attachment of the intermediate sections 14, 28 and 34 into the outer shear band ring 12. An adhesive interface 54 may be formed for the attachment of the intermediate sections 14, 28 and 34 to the outer shear band ring 12. The adhesive interface 54 may be a rubber based crosslinking material such as cushion gum that can be applied in a solid/skim or liquid form. Other adhesives used to form the adhesive interface 54 could be polyurethane, cyanoacrylate, or epoxy based glue. The adhesive forming the adhesive interface 54 may be applied to either the inner surface of the outer shear band ring 12, the outer surface of the various inner shear band rings 18, 32 and 38, or to both the outer shear band ring 12 and the inner shear band rings 18, 32 and 38.

[0029] Once the adhesive is applied, the intermediate section 14 may be collapsed some amount in the radial direction 22. The collapsing may be into any type of shape. This collapsing allows the intermediate section 14 to be inserted into the interior of the outer shear band ring 12 as the exterior diameter of the intermediate section 14 will be less than the inner diameter of the outer shear band ring 12. Once inserted, the intermediate section 14 will be allowed to return to its prior state so that the outer surface of the intermediate section 14 engages the interior surface of the outer shear band ring 12. Insertion of the intermediate section 14 into the outer shear band ring 12 is shown in Fig. 6 in which the position of the intermediate section 14 relative to the outer shear band ring 12 is shown.

[0030] The second and third intermediate sections 28 and 34 can likewise be collapsed, inserted, and expanded into the outer shear band ring 12. Fig. 7 shows the positioning of the second and third intermediate sections 28 and 34 into the outer shear band ring 12. The second intermediate section 28 engages both the first intermediate section 14 and the third intermediate section 34, and the first and third intermediate sections 14 and 34 are located at the axial ends of the outer shear band ring 12. The three intermediate sections 14, 28 and 34 when inserted extend along the entire width of the outer shear band ring 12 in the axial direction 24.

[0031] All the other intermediate sections 14, 28 and 34 can be collapsed, inserted and expanded at the same time, or they may be individually collapsed, inserted and expanded one after the other. The features of the intermediate sections 14, 28 and 34 can be arranged so that they are in register with one another, or they may be offset such that features such as spokes of the various intermediate sections 14, 28 and 34 are not aligned with one another in the axial direction 24.

[0032] Once the intermediate sections 14, 28 and 34 are positioned within the outer shear band ring 12, the adhesive interface 54 can be treated based upon the particular type of adhesive employed. The adhesive interface 54 can be cured by being treated with temperature, pressure and time sufficient to attain optimal curing as per the type of material used in the adhesive interface 54.

[0033] The next step in the assembly process may involve the attachment of the hub 20 to the intermediate section 14. Fig. 8 shows the hub 20 attached to the intermediate section 14. The attachment of the hub 20 may take place after the insertion and attachment of the intermediate sections 14, 28 and 34. The adhesive interface 54 may be cured before the hub 20 is attached, or alternatively the hub 20 may be attached to the end 62 before the adhesive interface 54 is cured.

[0034] With reference to Fig. 9, the non-pneumatic tire 10 is shown in partial cut away with the intermediate sections 14, 28 and 34 detached from the outer shear band ring 12 in the radial direction 22. The outer shear band ring 12 includes a series of circumferential reinforcements 66, and the various inner shear band rings 18, 32 and 38 likewise include a series of circumferential reinforcements 66. The circumferential reinforcements 66 may be made of fiberglass. The shear band rings 12, 18, 32 and 38 are all part of the shear band 56 and are not portions of the outer V pair spoke sections of the supporting structures 16, 30 and 36. The assembly described herein thus features the shear band 56 being provided as multiple parts that are subsequently assembled with one another into the resulting shear band 56. The inner shear band rings 18, 32 and 38 are not rings that are of the same material as the outer V pair spoke sections 44 of the supporting structures 16, 30 and 36, but are instead actual portions of the completed shear band ring 56.

[0035] As shown, the features of the intermediate sections 14, 28 and 34 are out of register from one another in Fig. 9. In this regard, the second intermediate section 28 is rotated relative to the first and third intermediate sections 14 and 34 in the circumferential direction 26 so that the spokes of the second intermediate section 28 are not aligned with the spokes of the first and third intermediate sections 14 and 34. The supporting structures 16 and 36 are in register with one another so that the spokes of the first and third intermediate sections 14 and 34 align in the circumferential direction 26. However, it is to be understood that the non-pneumatic tire 10 can be arranged in other manners so that all of the features of the sections 14, 28 and 34 such as the spoke are all aligned with one another in the circumferential direction 26 so that they are aligned end to end in the axial direction 24 so that from the side the first intermediate section 14 hides all of the features of the second and third intermediate sections 28 and 34 as illustrated for example in Fig. 8.

[0036] While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims.