Patent Application
20250187377
The present invention is directed to a non-pneumatic tire comprising spokes, particularly cord-reinforced spokes. Furthermore, the present invention is directed to a method of manufacturing a non-pneumatic tire comprising cord-reinforced spokes.
Some non-pneumatic tires comprise a supporting structure arranged between a tread band and a hub portion, wherein the supporting structure comprises a plurality of spokes. In some cases, such spokes comprise polymer material. In order to improve the durability of the spokes of non-pneumatic tires, spokes may be reinforced by cord or fiber material. While progress has been made in the provision of polymer spokes for non-pneumatic tires over the past years, significant room for improvement remains.
In a first aspect, the present invention is directed to a non-pneumatic tire comprising a radially outer circumferential band portion comprising a tread, a radially inner hub portion, and a supporting structure comprising a plurality of spokes extending between the hub portion and the circumferential band portion. At least one spoke of the plurality of spokes comprises a radially inner head portion adjacent the hub portion and a radially outer foot portion adjacent the circumferential band portion, wherein said at least one spoke further comprises a cord reinforcement wound between the foot portion and the head portion of the spoke.
In a second aspect, the present invention is directed to a non-pneumatic tire comprising a radially outer circumferential band portion comprising a tread, a radially inner hub portion, and a supporting structure arranged radially between the band portion and the hub portion. Furthermore, the supporting structure comprises a radially outer ring portion, a radially inner ring portion, and a plurality of spokes extending from the radially outer ring portion to the radially inner ring portion. Still in accordance with the second aspect, each spoke has a radially inner head portion and a radially outer foot portion, wherein at least two neighboring spokes of the plurality of spokes are reinforced by a common cord reinforcement, and wherein said cord reinforcement extends at least from the radially outer foot portion of one of the two neighboring spokes within said one of the two neighboring spokes to the radially inner head portion of said one of the neighboring spokes. Moreover, said cord reinforcement further extends through the radially inner ring portion into the radially inner head portion of the other spoke of the two neighboring spokes and further within the other spoke to a radially outer foot portion of the other spoke.
In a third aspect, the present invention is directed to a method of manufacturing a non-pneumatic tire, wherein the tire comprises a radially outer circumferential band portion comprising a tread, a radially inner hub portion, and a supporting structure comprising a plurality of cord-reinforced spokes extending between the hub portion and the circumferential band portion. Furthermore, said spokes have radially inner head portions and radially outer foot portions. The method comprises the steps of providing mold members for molding at least a circumferential sector of the supporting structure comprising one or more of the spokes; winding a cord reinforcement between radially outer foot portions and radially inner head portions of the one or more of the spokes in the circumferential sector of the supporting structure to be molded; and over-molding said cord reinforcement with a polymer composition to obtain the circumferential sector of the supporting structure comprising the one or more of the spokes.
The invention will be described by way of example and with reference to the accompanying drawings in which:
According to the first aspect, a non-pneumatic tire comprises a radially outer circumferential band portion comprising a (circumferential) tread or tread portion, a radially inner (circumferential) hub portion, and a (circumferential) supporting structure comprising a plurality of spokes extending between the hub portion and the circumferential band portion, particularly along the circumferential direction. At least one spoke of the plurality of spokes comprises a radially inner head portion adjacent the hub portion and a radially outer foot portion adjacent the circumferential band portion, wherein said at least one spoke further comprises a cord reinforcement which is, preferably continuously, wound, e.g., multiple times, between the foot portion and the head portion of the spoke. In particular, the provision of a continuous extending and/or wound cord reinforcement helps to provide an advanced supporting structure, circumferential sector thereof, and/or spokes with improved durability. Spoke deformations such as plastic deformations can be reduced or avoided. Moreover, such tires, supporting structures, circumferential sectors thereof, and/or spokes can be manufactured at large scale and/or cost efficiently.
In one embodiment, the spoke comprises a polymer composition. Preferably, the cord reinforcement extends within the polymer composition. Optionally, the spoke can be described as a cord-reinforced polymer composition spoke.
In still another embodiment, the spoke, and/or one or more of the spokes of the supporting structure, such as a majority or all of the spokes, comprise or have a cross-section, in a plane parallel to the equatorial plane of the tire, of one or more of: X-shapes, V-shapes, C-shapes, I-shapes, H-shapes, O-shapes, S-shapes, Y-shapes, half-X-shapes, and one or more of bent and kinked shapes/forms of the aforementioned shapes. Preferably, the shape is an X-shape, such as a straight or bent X-shape. Another preferred shape is a half X-shape, particularly corresponding to the shape of an X essentially cut in the radial direction. It is also possible to mention such a shape as an angled bracket shape or chevron shape, wherein its kink is not necessarily at the radial center of the shape.
In another embodiment, the spoke comprises or has an X-shaped cross-section (viewed in a plane in parallel to the equatorial plane of the tire, or a plane in parallel to the center line of the tire, or equivalent), preferably having one or more of a pair of radially outer legs, a pair of radially inner legs, and a crossing portion connecting the pair of radially outer legs with the pair of radially inner legs. Preferably, the spoke also has one or more of a radially inner connecting portion connecting radially inner ends of the radially inner legs, and a radially outer connecting portion connecting radially outer ends of the radially outer legs, such as in the circumferential direction. It is emphasized that it is possible that the X-shape may be curved, straight, symmetric, or asymmetric. In particular, one or more of said legs may comprise one or more of straight, kinked, and curved shapes, e.g., in said cross-section.
In still another embodiment, the cord reinforcement at least extends from a radially inner end of one of the radially inner legs through said one of the radially inner legs, further through the crossing portion into one of the radially outer legs, further through said one of the radially outer legs to a radially outer end portion of the one of the radially outer legs, and optionally further through the radially outer connecting portion to the radially outer end portion of another leg of the pair of radially outer legs. Also optionally, the cord reinforcement further extends through said another leg of the pair of radially outer legs towards and/or further through the crossing portion into another leg of the pair of radially inner legs. As further option, the cord reinforcement further extends to a radially inner end portion of said another leg of the pair of radially inner legs. Such a configuration is particularly durable.
In still another embodiment, the cord reinforcement passes or runs at least two times through the crossing portion. Optionally, the cord reinforcement extends transversely to itself and/or spaced apart (with respect to the axial direction) from itself through the crossing portion. Optionally, the cord reinforcement consists of at least one cord and/or a cord reinforced tape. Such an option may also apply to other embodiments herein.
In still another embodiment, the spoke comprises a polymer composition comprising one or more of an elastomer composition (preferably, a rubber composition) and a thermoplastic polymer, which is optionally reinforced by the cord reinforcement, such as at least one cord.
In still another embodiment, the polymer may be one or more of: i) one or more polyamide polymers (such as PA-12, PA-11, PA-6); ii) one or more thermoplastic polymers such as thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, polyamide thermoplastic elastomers, elastomer alloy thermoplastic vulcanizates, thermoplastic polyolefin elastomers, styrenic thermoplastic elastomers, thermoplastic resins (such as polyester resins, polyamide resins, or polyurethane resins). In particular, the term thermoplastic polymer shall include herein also thermoplastic resins.
In still another embodiment, the thermoplastic polymer is a thermoplastic elastomer, such as a thermoplastic polyester elastomer.
In another preferred embodiment, the polymer composition is an elastomer composition, such as a rubber composition. Optionally, said elastomer composition (such as the rubber composition) comprises one or more of rubber (such as comprising one or more of natural rubber, synthetic polyisoprene, butadiene rubber, styrene-butadiene rubber, and butyl rubber), a filler (such as comprising one or more of carbon black and silica), resin (such as a hydrocarbon resin selected from one or more of coumarone-indene resins, petroleum hydrocarbon resins, terpene resins, styrene/alphamethylstyrene resins, terpene phenol resins, rosin derived resins and copolymers and/or mixtures thereof), accelerators, antidegradants, oils, liquid diene-based polymers, coupling agents (such as carbon black coupling agents and/or silanes), sulfur donors, and sulfur. Liquid means herein that a material is in a liquid state at 23° C. The composition may be a sulfur-curable or sulfur-cured rubber composition. Optionally, elastomer compositions, such as rubber compositions may be fiber reinforced.
In still another embodiment, the elastomer composition or rubber composition comprises 100 phr of rubber comprising one or more of natural rubber, synthetic polyisoprene, polybutadiene rubber, and styrene butadiene rubber. Preferably, the composition comprises at least 50 phr of natural rubber (such as from 50 phr to 100 phr of natural rubber), and optionally from 0 phr (or 5 phr) to 50 phr of polybutadiene rubber. Additionally, the elastomer or rubber composition comprises a filler, preferably comprising carbon black and/or silica. For instance, such filler may be within a range of 20 phr to 150 phr, preferably within a range of 30 phr to 90 phr. Preferably, such a filler comprises predominantly carbon black. The elastomer or rubber composition may further comprise from 1 phr to 40 phr of resin, preferably including a phenolic resin. Moreover, the elastomer or rubber composition may comprise from 1 phr to 30 phr of oil, preferably from 1 phr to 20 phr of oil. Finally, the elastomer or rubber composition may typically comprise from 1 phr to 15 phr of antidegradant(s), from 0.5 phr to 10 phr of accelerator(s), from 0.1 phr to 10 phr of zinc oxide, and from 0.5 phr to 10 phr of sulfur. Further ingredients may also be present.
In still another embodiment, the spoke may comprise multiple polymer compositions such as multiple layers or portions of such compositions.
In still another embodiment, the cord reinforcement is selected from one or more of: i) at least one cord, ii) at least one cord-reinforced tape, and iii) at least one fabric comprising cords. In one option, the cord reinforcement comprises or consists of at least one cord. Preferably, a cord is one of a multifilament cord and a monofilament cord. In another option, a cord-reinforced tape comprises multiple essentially parallel cords, optionally embedded in and/or connected by a polymer composition, such as a resin composition, which may comprise one or more of polyester, vinyl ester, polyurethane, and epoxy, to form the tape. In another option, said fabric may comprise a plurality of, preferably interconnected, essentially parallel cords. Optionally, these cords may form warp cords and/or weft cords of the fabric.
In still another embodiment, the cord reinforcement, particularly one or more cords of the cord reinforcement, comprise or consist of one or more of textile material, glass fiber material, carbon fiber material, boron fiber material, basalt fiber material, plant-based material, and combinations of these materials. Optionally, multiple cords comprise different materials and/or are hybrid cords of such different materials. Optionally, said plant-based material comprises one or more of cotton, hemp, flax, sisal, and bast.
In still another embodiment, the cord reinforcement, particularly one or more cords of the cord reinforcement, comprise or consist of metal, such as steel or brass-coated steel.
In still another embodiment, the cord reinforcement, particularly one or more cords of the cord reinforcement, comprise or consist of a textile material selected from one or more of polyester (preferably, PET), polyamide (preferably, one or more of PA-6, PA-6,6, e.g., Nylon™, aromatic polyamide/aramid), and rayon. Optionally, one or more of these materials may be recycled materials. Optionally, multiple cords comprise different materials and/or are hybrid cords of such different materials.
In another embodiment, one or more cords provided herein are one of single filament and multifilament cords. For instance, cords may have (maximum) diameters measured perpendicular to the extension of the cord in the spoke within a range of 0.01 mm to 2 mm, preferably within a range of 0.01 mm to 1 mm.
In still another embodiment, the cord reinforcement is wound multiple times between the foot portion and the head portion, and/or multiple passes of the cord reinforcement between the foot portion and the head portion are spatially (and/or axially) separated from one another between the foot portion and the head portion. It is remarked that winding or passing of the cord reinforcement between the foot portion and the head portion shall not exclude that the cord reinforcement is wound and/or passes through said portions. Optionally, the cord reinforcement passes through said portions, or multiple cord reinforcements pass through said portions.
According to the second aspect, the present invention is directed to a non-pneumatic tire comprising a radially outer circumferential band portion comprising a (circumferential) tread or tread portion, a radially inner (circumferential) hub portion, and a supporting structure arranged radially between the band portion and the hub portion. Furthermore, the supporting structure comprises a radially outer (circumferential) ring portion, a radially inner (circumferential) ring portion, and a plurality of spokes extending from the radially outer ring portion to the radially inner ring portion, preferably along the circumferential direction. Still in accordance with the second aspect, each spoke has a radially inner head portion and a radially outer foot portion, wherein at least two (circumferentially) neighboring spokes of the plurality of spokes are reinforced by a common cord reinforcement, and wherein said cord reinforcement extends at least from the radially outer foot portion of one of the two neighboring spokes within the spoke to the radially inner head portion of said one of the neighboring spokes. Moreover, said cord reinforcement further extends through the radially inner ring portion into the radially inner head portion of the other spoke of the neighboring spokes and further within the other spoke to a radially outer foot portion of the other spoke. Thus, such neighboring spokes and the respective ring portion are reinforced by a common cord reinforcement, which improves the durability of the supporting structure or a circumferential sector thereof. Deformations of the supporting structure and/or spoke deformations such as plastic deformations can be reduced or avoided. Moreover, such tires, supporting structures, and/or spokes can be manufactured at large scale.
In one embodiment, the cord reinforcement extends through and/or reinforces a majority of the spokes of the tire.
In another embodiment, the cord reinforcement extends through multiple spokes along a circumferential sector of the tire and/or supporting structure or circumferential sector thereof.
In another embodiment, the cord reinforcement extends through at least 3, 4, 5, or 6 spokes of the tire and/or supporting structure or circumferential sector thereof.
In still another embodiment, the cord reinforcement extends at least two times around the tire so as to extend through each spoke at least two times. Preferably, when extending through the same spoke a second time, the cord reinforcement is axially spaced from itself in this spoke, such as being separated by a polymer composition of the spoke. Optionally, the cord reinforcement consists of at least one cord and/or a cord-reinforced tape.
In still another embodiment, the cord reinforcement extends multiple times between two circumferential end portions of a circumferential sector of the supporting structure, optionally passing multiple times (e.g., two times) through each spoke in the sector.
In still another embodiment, two neighboring spokes comprise each an X-shaped cross-section having one or more of a pair of radially outer legs, a pair of radially inner legs, and a crossing portion connecting the pair of radially outer legs with the pair of radially inner legs.
In still another embodiment, the cord reinforcement extends through one or more of a first radially outer leg of a first one of the two (circumferentially) neighboring spokes, further through the crossing portion of the first spoke, further through a first radially inner leg of the first spoke, and into the radially inner ring portion, and optionally from the radially inner ring portion into a first radially inner leg of a second spoke of the neighboring spokes and further through the crossing portion of the second spoke and into a first radially outer leg of the second spoke.
In still another embodiment, the cord reinforcement (further) extends from the radially outer leg of the second spoke through further spokes of the tire, optionally, around the tire. Preferably, the cord reinforcement extends into a second radially inner leg of the first one of the two neighboring spokes, further through the crossing portion of the first spoke and through a second radially outer leg of the first spoke into the radially outer ring portion, and from the radially outer ring portion into a second radially outer leg of the second spoke, further through the crossing portion of the second spoke and into a second radially inner leg of the second spoke.
In still another embodiment, the cord reinforcement extends at least two times through the crossing portion of each of the two neighboring spokes. Preferably, the cord reinforcement extends transversely to itself and/or axially spaced apart from itself through the crossing portion.
In still another embodiment, the cord reinforcement extending at least two times through each spoke is spatially, such as axially, separated from itself.
According to the third aspect, the method of making or manufacturing a non-pneumatic tire, wherein the tire comprises a supporting structure comprising cord-reinforced spokes, comprises the step of providing mold members for molding at least a circumferential sector of the supporting structure comprising one or more of the spokes. Furthermore, the method comprises the step of winding a cord reinforcement between radially outer foot portions and radially inner head portions of the one or more of the spokes in the circumferential sector of the supporting structure to be molded. Still in accordance with the third aspect, the method comprises the step of over-molding said cord reinforcement with a polymer composition to obtain the circumferential sector of the supporting structure comprising the one or more of the spokes.
Optionally, the method is used to make the tire according to the first aspect or the second aspect, and optionally in accordance with one or more respective embodiments.
In one embodiment of the method, the step of winding the cord reinforcement comprises winding the cord reinforcement (e.g., supported by one or more of the mold segments) at least from one of a radially outer foot portion and a radially inner head portion of a first spoke to the other one of the radially outer foot portion and the radially inner head portion of the first spoke, and optionally further from the other one of the radially outer foot portion and the radially inner head portion of the first spoke again to the one of the radially outer foot portion and the radially inner head portion of the first spoke, and from the one of the radially outer foot portion and the radially inner head portion of the first spoke again to the other one of the radially outer foot portion and the radially inner head portion. For instance, such a step may be performed to provide a spoke according to the first aspect, or one or more of its embodiments.
In another embodiment, the cord reinforcement is wound and/or supported on one or more mold members (such as mold inserts or mold core members), particularly before over-molding the cord reinforcement with the polymer composition. Directly winding the cord reinforcement on one or more mold members can provide an economical option for manufacturing. Optionally, the one or more cord reinforcements may be spaced from the surface of the mold members by one or more polymer layers.
In still another embodiment, the cord reinforcement is held at a distance from one or more adjacent mold members, such as mold inserts or mold core members, by protrusions on these mold members, optionally so as to at least predominantly encapsulate the cord reinforcement along its extension by over-molding of said cord reinforcement with the polymer composition.
In still another embodiment said protrusions are provided at edges of the one or more mold members. Optionally, said protrusions comprise a curved surface. Such a surface helps to avoid damaging the cord reinforcement.
In another embodiment, winding the at least one cord reinforcement comprises winding the cord reinforcement from a radially outer foot portion of a first spoke to a radially inner head portion of the first spoke and from the radially inner head portion of the first spoke to a radially inner head portion of a (circumferentially) neighboring second spoke, from the radially inner head portion of the second spoke to a radially outer foot portion of the second spoke, from the radially outer foot portion of the second spoke to a radially outer foot portion of a third spoke neighboring the second spoke on a side opposite to the first spoke, e.g., along the circumferential sector of the supporting structure. For instance, such an embodiment may be used to manufacture a tire, a supporting structure, or a circumferential sector (e.g., as such), such as according to the second aspect of the present invention, or one or more of its embodiments.
In still another embodiment, the supporting structure, or at least a circumferential segment or sector of the supporting structure, is manufactured, e.g., separately manufactured, by the method. For example, the supporting structure, or a circumferential sector thereof, preferably comprising multiple spokes, can be formed in a mold ring defining the shape of the supporting structure. In case of manufacturing a circumferential segment or sector of the supporting structure, such a segment or sector can, e.g., be manufactured with a corresponding ring segment or ring sector shaped mold.
In still another embodiment, the method comprises winding the cord reinforcement through further spokes of the tire around the tire and/or the circumferential sector of the supporting structure.
In still another embodiment, the cord reinforcement extends again into the first spoke after winding the cord through said further spokes of the supporting structure around the tire.
One of these spokes 130 is shown in detail in
In multiple embodiments and/or Figures herein, the circumferential direction c, the axial direction a, and the radial direction r, are indicated for better orientation. The circumferential direction c is perpendicular to the axial direction a. The same applies to the radial direction r. The axial direction a is parallel to the axis of rotation of the tire. Such directions mentioned herein are not necessarily limited to a specific orientation of the given direction, unless otherwise described herein.
In the schematic cross-section of
In this context,
Another embodiment of a supporting structure, or only a circumferential segment or sector 740 thereof, is shown in
While not shown in the embodiments herein above, another embodiment consists in that multiple circumferential rows of spokes are provided axially besides one another, such as two, three or four of such rows. From row to row, circumferential positions of such spokes could be the same or circumferentially shifted.
Molds, mold inserts and/or mold members are provided preferably with one or more temperature resistant materials, such as having a melting point higher than 200° C., preferably higher than 300° C. Plastic, ceramic or metal materials are non-limiting examples for such mold materials.
In summary, the present invention and its embodiments provide durable spokes, durable sectors of supporting structures, and/or durable supporting structures. Potential plastic deformations of the spokes can be avoided or at least reduced. Cord reinforcements can be placed in a determined manner and/or allow for large-scale production, particularly in a cost-efficient manner.
It is emphasized that the aspects, embodiments and features thereof as disclosed herein may be combined with one another.
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
