Non-pneumatic tire

Field of the Invention

0001The present invention relates to a non-pneumatic tire, in particular a non-pneumatic tire having a sidewall.

Background of the Invention

0002Recently, multiple tire manufacturers have suggested different designs of non-pneumatic tires. Most of these designs are based on a reinforced rubber shear band supported by a spoke structure on a tire hub or rim. Such tires typically have a laterally open side structure rather than a closed sidewall. While a sidewall may not be absolutely necessary in light of the fact that the tire does not need to enclose a pressurized air cavity, the appearance of such tires may be undesirable. Moreover, stones and dirt may enter in between the spoke structure which may result in an undesirable appearance, negatively affect the resilient function of the spokes or even damage the spokes. Therefore, it may be desirable to provide also a non-pneumatic tire with sidewalls so as to prevent foreign objects from entering the spoke structure and to improve the appearance of the tire. Moreover, non-pneumatic tires have been suggested that have essentially a circular rubber layer covering the space between the tread portion and the hub portion of the tire. However, such layers or sidewalls tend to bulge considerably in an axial direction under load and may in some cases also rupture due to the cyclic motion and flexing of the tire. While such sidewall bulging or rupture may not have an immediate impact on tire safety it is, of course, desirable to avoid such occurrences.

0003United States Patent <patcit id="pcit0001" dnum="US6298891B"><text>6,298,891</text></patcit> reveals a rim assembly adapted for use in supporting an associated tire fill medium and an associated tread in a non-pneumatic tire assembly, wherein said tread has a ground engaging surface extending between spaced first and second sides, and wherein said tire fill medium is radially inward of said tread and has spaced first and second sides, said rim assembly being characterized by a first rim member having a transversely extending support base including spaced first and second ends and a notch column radially extending from said first end of said support base, said notch column having a first notch adapted to hold said first side of said associated tread and a second notch adapted to hold said first side of said associated tire fill medium; a second rim member having a second notch column, said second notch column having a first notch adapted to hold said second side of said associated tread and a second notch adapted to hold said second side of said associated tire fill medium; a securing means for selectively securing said second rim member in predetermined relationship to said first rim member, said securing means selectively extending between said second rim member and said second end of said support base of said first rim member; and a connecting means extending from a radially inward surface of said support base, said connecting means being adapted to connect said first rim member to an associated vehicle.

0004United States Patent <patcit id="pcit0002" dnum="US8662122B"><text>8,662,122</text></patcit> describes a non-pneumatic tire comprising a plurality of springs, each spring comprising a first end portion, a second end portion, and an arching middle portion, each spring being interwoven with at least one other spring thereby forming a toroidal structure extending about an entire circumference of the non-pneumatic tire, the toroidal structure being at least partially coated with an elastomer such that the toroidal structure forms an anisotropic structure having different mechanical properties in the circumferential direction of the non-pneumatic tire and the radial direction of the non-pneumatic tire.

0005United States Patent <patcit id="pcit0003" dnum="US8931531B"><text>8,931,531</text></patcit> discloses a non-pneumatic tire comprising a plurality of springs, each spring comprising a first end portion, a second end portion, and an arching middle portion, each spring being interwoven with at least one other spring thereby forming a toroidal structure extending about an entire circumference of the non-pneumatic tire, the toroidal structure being at least partially coated with an elastomer, one end portion of at least one spring being secured to a first coiled bead spring adjacent to a rim.

0006United States Patent <patcit id="pcit0004" dnum="US9616713B"><text>9,616713</text></patcit> discloses a composite material comprising a plurality of springs forming a structure embedded within polyurethane, each spring being interwoven with at least one other spring thereby forming an entirely polyurethane-coated structure, the composite material forming a toroidal carcass structure extending about an entire circumference of a non-pneumatic tire, each spring including a first end portion, a second end portion, and an arching middle portion interconnecting the first end portion and the second end portion, each first end portion being secured to a first annular bead and each second portion being secured to a second annular bead, the first and second annular beads both being seated to a wheel rim such that the toroidal carcass structure is secured to the wheel rim wherein the springs are elliptical.

0007United States Patent <patcit id="pcit0005" dnum="US10040314B"><text>10,040,314</text></patcit> reveals a structurally supported non-pneumatic tire comprising: a ground contacting annular tread portion; a shear band; and a spoke disk connected to the shear band, wherein the spoke disk has two or more circumferential spokes joined together by an upper and lower connecting web, wherein each spoke has an axial thickness less than the axial thickness of the spoke disk, wherein the spring rate of the spoke disk is greater than the spring rate of the shear band. This patent further discloses a structurally supported non-pneumatic tire comprising: a ground contacting annular tread portion; a shear band; and a spoke disk connected to the shear band, wherein the spoke disk has two or more circumferential spokes joined together by an upper and lower connecting web, wherein the spring rate of the spoke disk is greater than the spring rate of the shear band, wherein the spokes are angled at an angle α with respect to the axial direction in the range of 60-80°. United States Patent <patcit id="pcit0006" dnum="US10040314B"><text>10,040,314</text></patcit> also describes a non-pneumatic tire comprising: a ground contacting annular tread portion; a shear band; and at least one spoke disk connected to the shear band, wherein the spoke disk has two or more circumferential spokes joined together by an upper and lower annular connecting web, wherein each connecting web extends the full axial width of the non-pneumatic tire, wherein each circumferential spoke has a spoke width (W) and an axial thickness (t), wherein a ratio of the spoke width to axial thickness (W/t) is in the range between 15 and 80.

0008United States Patent <patcit id="pcit0007" dnum="US10150334B"><text>10,150,334</text></patcit> discloses a wheel and tire assembly for a mobile vehicle comprising: an inner central hub; an outer shear band and tread structure mounted on the central hub; a spoke structure extending between the central hub and the shear band and tread structure, the spoke structure defining a plurality of cavities disposed concentrically about the central hub whereby the cavities allow the spoke structure to deflect under load; and a reinforcing membrane interlaced circumferentially and radially about the cavities for further tuning the flexibility of the spoke structure.

0009United States Patent <patcit id="pcit0008" dnum="US10286725B"><text>10,286,725</text></patcit> reveals a wheel for a mobile vehicle comprising: an outer flexible ring mounted to an inner central rim; and a spoke structure extending radially between the central rim and the flexible ring, the spoke structure defining a plurality of closed cavities and an alternating plurality of radially extending openings disposed concentrically about the inner central rim and allowing the flexible ring to deflect under load, the spoke structure further defining a plurality of triangular openings disposed at the outer flexible ring and between the cavities and the inlet openings, the spoke structure comprising a uniform rubber material.

0010United States Patent <patcit id="pcit0009" dnum="US10308134B"><text>10,308,134</text></patcit> discloses a support assembly for a vehicle travelling along a road surface and rotating relative to the road surface and the vehicle comprising: a spherical tread layer for contacting the road surface; a foam layer adjacent the spherical tread layer, the foam layer including adjustable elements for altering an outer physical contour of the spherical tread layer, the outer physical contour contacting the road surface; a spherical wheel/tire for supporting the spherical tread layer and the vehicle; and a drive system magnetically driving rotation of the spherical wheel/tire relative to the vehicle such that no portion of the spherical tread layer physically contacts the vehicle, the drive system including a radially extending fiber optic element for external communication, a radially extending electronic communication/power bus, and an energy harvester disposed in the foam layer.

0011United States Patent <patcit id="pcit0010" dnum="US10350945B"><text>10,350,945</text></patcit> discloses a non-pneumatic tire and wheel assembly comprising: a ground contacting annular tread positioned radially outward of a shear band; a reinforcement layer positioned radially inward of the tread, said reinforcement layer being formed of one or more strips oriented in a geodesic path, wherein a radially inner end of the one or more strips is clamped to a wheel rim without the use of a bead, and a radially outer end of the one or more strips is secured between the tread and a shear band.

0012United States Patent <patcit id="pcit0011" dnum="US10414209B"><text>10,414,209</text></patcit> reveals a non-pneumatic tire comprising a ground contacting annular tread portion; a shear band; and a reinforcement structure positioned radially inward of the tread, said reinforcement structure being formed from a plurality of strips, wherein each strip has a first end located radially outward of the shear band and a second end secured to a bead, wherein the plurality of strips do not extend completely across the annular tread portion.

Summary of the Invention

0013One object of the present invention may be to provide an advanced non-pneumatic tire.

0014Another objective of the present invention may be to provide a non-pneumatic tire which prevents or reduces the possibility of foreign objects entering the volume between a hub portion and a tread portion of the tire.

0015Another object of the present invention may be to provide a non-pneumatic tire with an improved visual appearance when viewed from the side, in particular when loaded.

0016Another object of the present invention may be to provide an aerodynamically improved non-pneumatic tire. The improved aerodynamic design of such tires can lead to reduced air resistance or drag which facilitates higher speeds and better electrical energy and/or fuel economy.

0017The scope of protection of the present invention is defined by independent claim 1. Further preferred embodiments are recited in the dependent claims and the aspects and embodiments provided in the summary and description herein below.

0018Thus, in a first aspect of the invention, a non-pneumatic tire is provided, the tire comprising a hub portion, a ring member arranged essentially concentrically about (and radially spaced apart from) the hub portion, wherein the ring member comprises a tread portion on its radially outer(most) side (or surface). Moreover, the sidewall connects the hub portion with the ring member, or in other words, extends from the hub portion to the ring member, wherein the sidewall comprises multiple sidewall members, each sidewall member being connected on a first side, or in other words first end, (of the sidewall member) to the hub portion and on a second side, or in other words second end, (of the sidewall member) to the ring member. Adjacent sidewall members at least partially overlap (such as in the circumferential direction) so that they can move relatively to each other when loading and/or unloading the tire. The tire in accordance with this first aspect of the invention comprises a new sidewall concept which comprises a plurality of sidewall members. Adjacent sidewall members overlap at least partially so as to at least partially or fully cover the lateral side of the tire. Moreover, said overlap means that the members lie at least partially on top of each other with respect to the axial direction. Thus, the sidewall members may for instance slide relatively to each other, such as in a circumferential direction, or bend, such as in an axial direction. Large bulges are avoided. In particular, such a tire of a parked car does not or only slightly bulge in an area close to the ground as the sidewall members can relatively move to each other when the tire is loaded. Similarly, when driving, the sidewall members can periodically increase and decrease overlap, such as in an area close to the ground, as the tire rotates on the ground. Moreover, the provision of a plurality of sidewall members each separately attached to the hub portion and the ring member helps to avoid stresses over large sidewall surface areas, in particular compared to the provision of a one-piece sidewall cover.

0019In one embodiment, the sidewall members are plate-like members, wherein each plate-like member is attached at a first end or face side (of the plate-like sidewall member) to a radially outer side of the hub portion and at a second end or face side (of the plate-like sidewall member) to a radially inner side of the ring portion. In particular, the provision of plate-like sidewall member which may move relatively to one another is a particularly desirable way to provide a tire sidewall with limited bulging under load. In such an embodiment, the plate-like sidewall members extend essentially in a radial and circumferential direction. In other words, the thickness of the plate-like members extends essentially in the axial direction.

0020In another embodiment, the sidewall members at least partially cover a lateral side of the tire. Thus, a space between the ring member and the hub portion is not visible and protected from dirt and stones. Optionally, resilient spokes may extend between the hub portion and the ring member so that such spokes or spoke structures are also protected from elements entering through the side of the tire.

0021In still another embodiment, adjacent sidewall members at least partially overlap in an axial direction. This helps to allow a relative motion or sliding motion, e.g. in parallel to the plate-like sidewall members.

0022In yet another embodiment, adjacent sidewall members are configured to slide against each other upon loading the tire. In other words, the sidewalls members may overlap in a circumferential direction and slide relatively to each other, e.g. in the circumferential and/or radial direction. In further words, adjacent sidewall members are offset in an axial direction so that they can move relatively with respect to each other in circumferential and/or radial directions.

0023In yet another embodiment, from 6 to 60 (preferably from 10 to 30) sidewall members are arranged circumferentially around the tire. In particular, two neighboring sidewall members overlap. It is desirable that the sidewall comprises at least 6 sidewall members, in particular plate-like members so as to reduce the tendency of bulging of the sidewall. The upper limit of 60 is not mandatory but constitutes a reasonable number to limit complexity of the sidewall construction.

0024In yet another embodiment, one or more of the sidewall members are essentially sickle-shaped, e.g. preferably plate-like sickle shaped members. Optionally, such members extend essentially transversally from the hub portion and/or join the ring portion at an angle smaller than 45°, preferably smaller than 25°. Closing the tire with a sidewall improves the aerodynamic properties of the tire. Moreover, when providing overlapping sickle-shaped members, said aerodynamics can be further improved, especially when the curvature of the sickle shapes follows the rotational movement of the tire.

0025In still another embodiment, each sickle-shaped sidewall member is attached to the hub portion at a first circumferential position and attached to the ring member at a second circumferential position, wherein the first circumferential position and the second circumferential position are shifted relatively to each other by an angle of at least 10°, measured in the circumferential direction about an axis of rotation of the tire (in other words in a plane parallel to the equatorial plane of the tire).

0026In still another embodiment, the first circumferential position and the second circumferential position are shifted by between 20° and 150°, preferably between 60° and 130°.

0027In still another embodiment, the first face side is attached to the hub portion at an angle from 1° to 45° (preferably from 2° to 10°) with respect to an equatorial plane of the tire, in other words measured preferably perpendicular to the equatorial plane of the tire. This arrangement helps to ease sliding of the sidewall members relative to each other. Preferably, the interface of a first plate-like element with the hub portion is essentially in parallel to an interface of an adjacent second plate-like element with the hub portion but offset from each other in an axial direction while one circumferential end of the interface of the first plate-like element overlaps with the interface of the second plate-like element. Thus, when viewing in an axial direction there is no slot visible between two adjacent sidewall members as they overlap.

0028In another embodiment, the second face side is attached to the ring portion at an angle from 1° to 45° (preferably from 2° to 10°) with respect to an equatorial plane of the tire. Thus, similarly to the interface between the sidewall members and the hub portion, the interface at which the sidewall member is attached to the radially inner side or surface of the ring member is slightly tilted with respect to the equatorial plane of the tire. This tilt at the given angles facilitates a sliding motion between two adjacent sidewall members. Again the interfaces of two neighboring sidewall members are offset in an axial direction. When viewed in the axial direction, the neighboring sidewall plates overlap each other such that no slot is visible between them when viewed in the axial direction. Preferably, this applies to the loaded and/or non-loaded tire.

0029In another embodiment, two adjacent plate-like elements, or two adjacent sidewall members in general, at least partially overlap along their extension from the hub portion to the ring member. Preferably, they overlap along at least 80% of their extension from the hub portion to the ring element. Even more preferably, two neighboring sidewall elements overlap along at least 90% or even along 100% of their length between the hub portion and the ring member. This applies again to the loaded or non-loaded tire.

0030In still another embodiment, the first end or face side extends over a length of between 2% and 20% of the radially outer circumference of the hub portion. Even if said end or face side does not extend exactly along the circumferential direction, e.g. as described herein above, it extends over a certain circumferential length (i.e. projected onto the circumferential direction). It is not desirable to have substantially higher extensions with respect to the circumferential direction as this may increase again sidewall stresses when the tire is loaded and may thus result in relatively large deformations, bulging and may also lead to crack formation.

0031In still another embodiment, said second end or face side extends over a length of between 2% and 20% of the radially inner circumference of the ring member. As the radially inner circumference of the ring member will be larger than the outer circumference of the hub portion, the length of the connection line of the second end or face side with the radially inner side of the ring member will typically be longer than a corresponding connection line between the hub portion and the first face side.

0032In still another embodiment, the sidewall members overlap in a non-loaded state by at least 2 mm (and preferably by at most 20 mm) over at least 50% (preferably at least 80%, or even over 100%) of their extension from the hub portion to the ring member. Such an overlap helps to avoid debris entering the space between the hub portion and the ring member.

0033In still another embodiment, said sidewall members are made of rubber formulations, thermoplastic elastomers, plasticized thermoplastics, polyurethanes, or other flexible polymeric materials. For instance, the sidewall member can comprise a cured (vulcanized) natural or synthetic rubber, such as high cis-1,4-polybutadiene rubber, synthetic polyisoprene rubber, styrene-butadiene rubber, and the like, or blends thereof. The sidewall member can also comprise a thermoplastic elastomer, such as a butadiene/styrene diblock polymer, a styrene/butadiene/styrene triblock polymer, or a butadiene/styrene/butadiene triblock polymer. The sidewall member can also be a plasticized thermoplastic, such as a highly plasticized polyvinylchloride or highly plasticized polyolefin (polyethylene or polypropylene).

0034In still another embodiment, the tire has two opposite lateral sides, wherein the tire has only one lateral side partially or fully covered with a sidewall (in particular the sidewall in accordance with an embodiment according to the present invention). Leaving one sidewall open, helps to drain water which may enter the space between the hub portion and the ring member. The same applies to dirt or stones, in case any of those where to enter the space between the hub portion and the ring member between the sidewall members. Such an embodiment would rather focus on the appearance of the tire. This configuration allows also cleaning and/or inspecting a spoke structure between the hub portion and the ring member. The tire may then be mounted on a vehicle in a manner that the sidewall is opposite to the wheel hub.

0035In an embodiment, the hub portion has an essentially hollow cylindrical shape. In such a configuration, the tire may be mounted on a rim fitting the inner diameter of the hub portion.

0036In another embodiment, the hub portion may be configured for connection to a wheel hub of a vehicle. For instance, the hub portion may comprise axial apertures for receiving bolts or stay bolts for mounting the non-pneumatic tire to a vehicle wheel hub.

0037In still another embodiment, a lateral side opposite to said sidewall of the tire has at least one aperture for draining water (or for inspection purposes).

0038In still another embodiment, the sidewall members resiliently support the ring member on the hub portion. Thus, apart from the function of covering the side of the tire against dirt and stone, the sidewall members may also have a supporting function. It is possible that this function at least partially replaces resilient spokes extending between the hub portion and the ring member.

0039In still another embodiment, the tire further comprises spokes and/or a spoke structure, or in other words supporting structure, resiliently supporting the ring member on the hub portion. Preferably, such a structure is arranged between the laterally opposite sides of the tire within a space between the hub portion and the ring member. Supporting structures of various types and designs are known in the prior art of non-pneumatic tires.

0040In still another embodiment, said spokes are arranged axially inside of the sidewall members.

0041In another embodiment, said spokes have essentially rod-like shapes and may optionally have a thickness within a range of 2 mm to 10 mm, preferably from 3 mm to 6 mm.

0042In still another embodiment, said sidewall members may have an axial thickness within a range of 3 mm to 30 mm, 3 mm to 10 mm, 10 mm to 30 mm. Larger thicknesses may be preferred in case the sidewall has also a supporting function. Thinner thicknesses may be preferred in case the sidewall has rather only a covering function.

0043In still another embodiment, the ring member comprises a reinforced polymer material. The ring member may also be called a shear band as used in the field of non-pneumatic tires. Such shear bands are described in greater detail in United States Patent <patcit id="pcit0012" dnum="US9834040B"><text>9,834,040</text></patcit>, United States Patent <patcit id="pcit0013" dnum="US9849721B"><text>9,849,721</text></patcit>, United States Patent <patcit id="pcit0014" dnum="US10040314B"><text>10,040,314</text></patcit>, United States Patent <patcit id="pcit0015" dnum="US10040317B"><text>10,040,317</text></patcit>, United States Patent <patcit id="pcit0016" dnum="US10071603B"><text>10,071,603</text></patcit>, United States Patent <patcit id="pcit0017" dnum="US10150334B"><text>10,150,334</text></patcit>, United States Patent <patcit id="pcit0018" dnum="US10207544B"><text>10,207,544</text></patcit>, United States Patent <patcit id="pcit0019" dnum="US10259179B"><text>10,259,179</text></patcit>, United States Patent <patcit id="pcit0020" dnum="US10286725B"><text>10,286,725</text></patcit>, United States Patent <patcit id="pcit0021" dnum="US10350945B"><text>10,350,945</text></patcit>, United States Patent <patcit id="pcit0022" dnum="US10384409B"><text>10,384,409</text></patcit>, United States Patent <patcit id="pcit0023" dnum="US10406852B"><text>10,406,852</text></patcit>, United States Patent <patcit id="pcit0024" dnum="US10414209B"><text>10,414,209</text></patcit>, United States Patent <patcit id="pcit0025" dnum="US10457094B"><text>10,457,094</text></patcit>, and United States Patent <patcit id="pcit0026" dnum="US10471773B"><text>10,471,773</text></patcit>. The teachings of United States Patent <patcit id="pcit0027" dnum="US9834040B"><text>9,834,040</text></patcit>, United States Patent <patcit id="pcit0028" dnum="US9849721B"><text>9,849,721</text></patcit>, United States Patent <patcit id="pcit0029" dnum="US10040314B"><text>10,040,314</text></patcit>, United States Patent <patcit id="pcit0030" dnum="US10040317B"><text>10,040,317</text></patcit>, United States Patent <patcit id="pcit0031" dnum="US10071603B"><text>10,071,603</text></patcit>, United States Patent <patcit id="pcit0032" dnum="US10150334B"><text>10,150,334</text></patcit>, United States Patent <patcit id="pcit0033" dnum="US10207544B"><text>10,207,544</text></patcit>, United States Patent <patcit id="pcit0034" dnum="US10259179B"><text>10,259,179</text></patcit>, United States Patent <patcit id="pcit0035" dnum="US10286725B"><text>10,286,725</text></patcit>, United States Patent <patcit id="pcit0036" dnum="US10350945B"><text>10,350,945</text></patcit>, United States Patent <patcit id="pcit0037" dnum="US10384409B"><text>10,384,409</text></patcit>, United States Patent <patcit id="pcit0038" dnum="US10406852B"><text>10,406,852</text></patcit>, United States Patent <patcit id="pcit0039" dnum="US10414209B"><text>10,414,209</text></patcit>, United States Patent <patcit id="pcit0040" dnum="US10457094B"><text>10,457,094</text></patcit>, and United States Patent <patcit id="pcit0041" dnum="US10471773B"><text>10,471,773</text></patcit>.

0044In still another embodiment, the tread portion is made of a rubber material. The rubber material of which the tread is comprised can be a natural rubber or a synthetic rubber. This rubber material will typically be a blend of various rubbers including one or more of natural rubber, high-cis-1,4-polybutadiene rubber, solution styrene-butadiene rubber (SSBR), emulsion styrene-butadiene rubber (ESBR), synthetic polyisoprene rubber, isoprene-butadiene rubber, and the like.

0045The above embodiments may be combined with one another, optionally also with the features mentioned in the detailed description of the invention as described herein below.

Brief description of the drawings

0046The structure, operation, and advantages of the invention will become more apparent upon contemplation of the following description taken in conjunction with the accompanying drawings, wherein <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> is a schematic side view of a tire in accordance with a first embodiment of the invention.</li><li><figref idref="f0001">Figure 2a</figref> is a schematic partial cross section looking along the radial direction onto a radially outer side of the hub portion with attached sidewall members;</li><li><figref idref="f0001">Figure 2b</figref> is a schematic partial cross section looking along the radial direction onto a radially outer side of a hub portion with attached sidewall members according to an alternative embodiment of the invention;</li><li><figref idref="f0002">Figure 3</figref> is a schematic perspective view of an exemplary spoke structure in accordance with an embodiment of the present invention, whereas the sidewalls and the tread portions are not shown for the sake of clarity; and</li><li><figref idref="f0002">Figure 4</figref> is a schematic sideview of the spoke structure already shown in <figref idref="f0002">Figure 3</figref>.</li></ul>

Detailed Description of the Embodiments

0047<figref idref="f0001">Figure 1</figref> shows an embodiment of a non-pneumatic tire 1 comprising a central hub or hub portion 2, a shear band or ring member 3 carrying a tread portion 5, wherein the hub portion 2 and the ring member 3 are connected by a sidewall 7 comprising a plurality of plate-shaped sidewall members 6. The sidewall members 6 have in this non-limiting embodiment a sickle-shape, wherein each sidewall member 6 is connected at one end to the central hub portion 2 and at the opposite end to the ring member 3. This sidewall structure is preferably provided only on one lateral side of the tire 1 but may also be provided on both lateral sides of the tire 1. Upon loading the tire 1, e.g. when the tire 1 is mounted to a vehicle, the tire 1 will deform and the sickle-shaped sidewall members 6 can slide relative to each other so as to keep the space between the hub portion 2 and the ring member 3 laterally covered. In particular, it may be avoided by such means that dirt and stones enter the space between the hub portion 2 and the ring member 3. Considerable bulging of the sidewall 7 can be avoided. The sickle-shaped members 6 extend from a first angular position at which they are connected to the hub portion 2 to a second (different) angular position at the ring member 3. This has been illustrated for one sidewall member by the angle β in <figref idref="f0001">Figure 1</figref>, which is in the drawing in the order of 120°. The angle β is measured in a plane perpendicular to the axial direction a of the tire 1. The indicated radial direction r is also perpendicular to the axial direction a. The circumferential direction c is parallel to the circumference of the tire 1 and parallel to the equatorial plane of the tire (not shown in <figref idref="f0001">Figure 1</figref>).

0048<figref idref="f0001">Figure 2a</figref> is a partial cross-section through some sidewall members 6 viewed along the radial direction r. The sidewall members 6 overlap essentially in a circumferential direction c so that when viewed in the axial direction there is no slot left between adjacent sidewall members 6. In other words, neighboring sidewall members are at least partially axially offset with respect to each other. Moreover, in order to allow a sliding motion in a direction s, which is almost in parallel to the circumferential direction c, the sidewall members have a non-zero angle α with the circumferential direction c. Said angle α is within a range of 5° to 10°. In particular, trailing edges of adjacent sidewall members 6, or preferably of all sidewall members 6, are arranged at the same axial position along the circumference of the hub portion 2. The same applies to the leading edges of the sidewall members 6 which are arranged at the same axial position along the circumferential direction, wherein the axial position of the leading edges is different than the axial position of the trailing edges, in other words said position are axially offset. Similarly to the attachment and/or arrangement of the sidewall members 6 at the hub portion 2, the sidewall members 6 are also attached to the radially inner side of the ring member 3. The sidewall members 6 may join the radially inner side or surface of the ring member 3 at the same or similar angles as suggested herein for the attachment of the sidewall members 6 to the hub portion 2.

0049<figref idref="f0001">Figure 2b</figref> shows an alternative embodiment in accordance with the invention with respect to the embodiment already described in the context of <figref idref="f0001">Figure 2a</figref>. According to <figref idref="f0001">Figure 2b</figref>, adjacent sidewall members 6' attached to a hub portion 2' can slide relatively to each other along the circumferential direction c. The preferred direction of motion has been further indicated by the sliding direction s' which is in parallel with the circumferential direction c. In other words, adjacent sidewall members 6' are axially offset and (partially) overlap in a circumferential direction. Thus, when viewed in the axial direction the sidewall fully covers the interior of the tire. In accordance with the embodiment shown in <figref idref="f0001">Figure 2b</figref>, it is preferred that the axial positions of the sidewall elements 6' alternate between a first and a second axial position such that a first sidewall member 6' is axially offset with regard to the position of a circumferentially adjacent second sidewall member 6' and that a third sidewall member 6' adjacent the second sidewall member 6' has again essentially the same axial position as the first sidewall member 6. In other words, each second sidewall member 6' (in the circumferential direction) is axially offset with respect to the remaining sidewall members. In such an embodiment, the number of sidewall members 6' is preferably even.

0050When making reference herein to axial, radial or circumferential directions (a, r, c), these terms shall be understood as commonly understood in the tire art. In particular, a reference to an axial direction means a direction in parallel to the axis of rotation of the tire. A reference to the circumferential direction is a direction concentric about the axis of rotation of the tire and/or in parallel to an equatorial plane of the tire. The radial direction is perpendicular to the axis of rotation of the tire. The equatorial plane of the tire is also a term which is known to the person skilled in the tire art. In particular it is perpendicular to the axis of rotation of the tire and separates the tire into two equal parts (each of which constitute one-half of the tire).

0051Axially or laterally behind the sidewall 7 comprising the sidewall members 6, the tire 1 may comprise a plurality of spokes or a spoke structure (not shown in <figref idref="f0001">Figures 1 and 2</figref>) resiliently supporting the ring member 3 on the hub portion 2.

0052<figref idref="f0002">Figures 3 and 4</figref> show a non-limiting embodiment of such spokes 4, which are preferably made of carbon fiber-based material and are arranged in twelve pairs of groups about the circumference of the tire 1. The spokes 4 extend in general from the radially outer surface of the hub portion 2 to the radially inner surface of the ring member 3. Each pair of groups consists of a first group of spokes 4 extending from a line adjacent and along a first axially outer edge of the ring member 3 towards the hub portion 2, wherein the spokes 4 cross beside each other adjacent a crossing point 12 between the hub portion 2 and the ring member 3 and further extend towards and onto the hub or hub portion 2. As shown in <figref idref="f0002">Figure 3</figref>, the spokes 4 connect to the hub portion 2 at axial positions which are closer to the axial center of the hub portion 2 than the axial positions at which the spokes 4 of the first group are attached to the ring member 3. The second group of spokes 4 of the same pair (each group of the pair being essentially arranged at the same circumferential position or angle) extends from a line adjacent and along a second axially outer edge of the ring member 3 (axially opposite to said first edge) towards the hub portion 2. The spokes 4 of the second group cross beside each other adjacent a common crossing point between the hub portion 2 and the ring member 3 and further extend towards and onto the hub portion 2. Again the spokes 4 connect to the hub at axial positions which are closer to the axial center of the hub portion 2 than the axial position at which the spokes 4 of the second group are attached to the ring member 3. Such an arrangement may improve the stiffness of the tire 1 with regard to lateral forces.

0053Moreover, as shown in <figref idref="f0002">Figure 3</figref>, the spokes 4 of a group (sharing a common crossing point 12) are preferably attached to the hub portion 2 along a non-straight line extending in the axial and circumferential directions. Such an arrangement improves stability with regard to lateral forces further. Preferably, the crossing points 12 of all pairs have a radial distance to the radially outer surface of the hub portion 2 which is less than 50% (even more preferably between 45% and 25%) of the radial distance between the radially outer side of the hub portion 2 and the radially inner side of the ring member 3.

0054While the spokes have been shown in accordance with <figref idref="f0002">Figures 3 and 4</figref> as rod-like elements, such spokes may for instance have plate-like shapes and/or a lattice-like or grid-like structure. Thus, in an embodiment of the invention, the resilient supporting structure arranged between the hub portion 2 and the ring member 3 can be provided as known in the existing art of non-pneumatic tires. In an example, the ring member could be circumferentially supported on the hub portion 2 by a resilient supporting structure extending about the hub portion 2 to support the ring member 3 on the hub portion 2.

0055In general, hub portion 2, spokes 4, sidewall members 6 and the shear band or ring member 3 may comprise a polymer material or composition.