WO2004024470A1

WO2004024470A1 - Vehicle wheel with non-pneumatic casing

Info

Publication number: WO2004024470A1
Application number: PCT/FR2003/002690
Authority: WO
Inventors: Jean Gergele
Original assignee: Jean Gergele
Priority date: 2002-09-12
Filing date: 2003-09-10
Publication date: 2004-03-25
Also published as: AU2003278300A1

Abstract

The invention concerns a vehicle wheel (2) comprising a rim (7) connected directly or via a disc (4) to a hub (3) of the vehicle and a non-pneumatic casing (9) comprising: a globally cylindrical or doughnut-shaped running tread (10), an annular part (13), constituting the belt of the non-pneumatic casing (9), fixed beneath the running tread (10), and two truncated flexible sidewalls (14, 15) linking the annular part (13) to the rim (7). Each sidewall (14, 15) comprises reinforcing cord fabrics (33, 35), each cord being separated from the other elements constituting the wheel (2) by at least one layer (34) of a material with low friction coefficient and non-adhering to the elastomer mixtures of the other elements constituting the wheel (2).

Description

VEHICLE WHEEL WITH NON-PNEUMATIC HOUSING

The present invention relates to a wheel for a vehicle of the non-pneumatic type.

In the rest of the text, the term calender applies to a layer of cables connected together by a mixture of elastomers. An uncalendered cable ply is a cable ply not connected by a mixture of elastomers.

On the other hand, in the following text, the median plane of a wheel designates the plane perpendicular to the axis of rotation of the wheel and passing substantially through the middle of the width of the tread. The pneumatic casing wheels, most often radial, achieve a very high level of longevity, grip, comfort, while the noise pollution attributable to the wheel has been considerably reduced.

However, the punctures inherent in a pneumatic envelope, that is to say inflated with a gas under pressure, remain possible. The risk of leakage involves monitoring the inflation pressure and, more often than not, the presence of a spare wheel and therefore a place to house this wheel in the vehicle. Numerous devices have been proposed either for monitoring the pressure of the pneumatic casings of the wheels, today called tires, or for attempting to eliminate the spare wheel by allowing degraded use of the wheel while awaiting its replacement.

Known solutions exist, however, to provide a definitive answer to the problem of puncture and flattening.

These solutions consist in particular in increasing the rigidity of the inextensible belt supporting the tread, thus enabling the envelope to carry the load without the aid of the inflation pressure. They are described in the patents or patent applications WO01 / 42033, US4673014, US4241775 and US4456048, US1502908 and FR1041576.

All these documents describe non-pneumatic envelopes, the pneumatic term implying that they are inflated.

However, the devices described in these documents have sidewalls which can only support a limited load or which have significant resistance to advancement, since they are inspired by the radial or crossed structures used on the pneumatic casings. Cross structures are well suited to wheels carrying high loads, but imply, due to their structure, poor performance in resistance to travel, because of the hysteresis of the mixtures of elastomers present, causing significant overheating.

On the other hand, these devices do not allow for simple mounting and effective maintenance on the rim of such non-pneumatic casings.

The object of the present invention is to provide a solution to these technical problems.

To this end, the subject of the present invention is a vehicle wheel comprising a rim connected directly or via a disc to a hub of the vehicle and a non-pneumatic type casing comprising:

- a generally cylindrical or toroidal tread,

- an annular part, constituting the inextensible belt of the non-pneumatic casing, fixed to the tread, radially inside the latter, and - two flexible sides of frustoconical shape connecting the annular part to the rim, characterized in that each side has plies of cables or reinforcing wires, each cable or wire being separated from the other constituent elements of the wheel by at least one layer of a material with a low coefficient of friction and not adhering to the others wheel components,

- a layer of this material being placed individually on each cable or wire, or constituted by a physico-chemical treatment of the surface of the cables or of the reinforcing wires, and / or - a layer of this material being disposed between the layers of cables or neighboring wires and between the plies of cables or wires and the mixtures of elastomers or other constituent elements of the surrounding wheel.

This arrangement makes it possible to eliminate the effects of hysteresis of the mixtures of elastomers surrounding the cables, since the latter deform independently of said mixtures and do not transmit any stress to them. The structure obtained has low resistance to advancement.

Advantageously, the flexible sides comprise at least two plies of crossed cables or wires, calendered or non-calendered, as well as a protective layer, in particular made from elastomers, situated on the outside of the envelope, and in that '' a layer of low friction material is placed between two layers of cables or wires adjacent and between the protective layer and the cable or wire layer adjacent to the protective layer.

The crossed plies, used with the arrangement described above, make it possible, in association with an adequate stiffness belt, without inflation pressure, to support significant loads.

Advantageously, at least a portion of the cables or wires for reinforcing the sidewalls projects onto a plane perpendicular to the axis of rotation of the wheel according to straight line segments substantially tangent to a circle, concentric with the rim, of diameter greater than the part of the rim 7 called seat on which the sidewall bears radially.

The arrangement in “tangents” of the sidewall reinforcements makes it possible to achieve a high load capacity of the non-pneumatic envelope, without degrading the rolling resistance.

According to one embodiment, the annular part comprises two lateral circular reinforcements whose rigidity in total bending, that is to say of the two reinforcements considered together, represents at least 10% of that of the annular part, the axis of bending considered being parallel to the axis of rotation of the wheel and located in the vicinity of the center of gravity of the section of the annular part, each of them being connected to the annular part and disposed near the connection zone of a of the two flexible sides therewith.

Advantageously, the connection of the sidewalls to the rim imposes a prestress in tension of the sidewalls.

Advantageously, the areas of connection of the two sidewalls to the rim are closer to the median plane of the wheel than the areas of connection of the sidewalls to the annular part, and each sidewall has, on its edge intended to be in connection with the rim , a non-expandable circular bead, the two beads being held in position by corresponding hooking means located on the rim at two locations separated by a distance less than the resting distance of the two beads, thereby creating the required tension preload flanks.

According to one possibility, the rim is removable in several parts allowing the establishment of the beads of the envelope on the attachment means.

According to another possibility, the attachment means comprise: - at a first location located on the edge of the rim on the side opposite to the side of introduction of the casing on the rim, a first flange of diameter greater than the diameter of the first circular bead and constituting a lateral stop for the first bead simultaneously pressing on the first seat of the rim, and,

- on a second location located on the edge of the rim on the side of the introduction, an annular groove, of minimum diameter less than the diameter of the second seat of the rim, in which is housed a flexible annular bead formed on the edge of the second bead allowing the latter to be held in position, the groove being delimited upstream in the direction of introduction by a second rim of the rim, of diameter close to the diameter of the second bead and allowing the passage of the two beads during assembly of the casing on the rim.

This arrangement which makes it possible to easily assemble the envelope with limited deformation of the beads of the envelope is particularly suitable for non-pneumatic envelopes, the sides of which have a slightly deformable end bead.

Advantageously, at least one circular safety boss is formed on the outer surface of the rim between one of the support seats of one of the beads and the median plane, the maximum diameter of this boss being slightly greater than that of the seat. . According to one embodiment, the heel is made of an elastic material and reinforced by elastic cables arranged in a circular pattern.

Advantageously, the maximum slope of the surface of revolution connecting the bottom of the groove to the second flange, angle measured from the axis of rotation of the wheel, is greater than 45 °. According to one possibility, the annular part consists of at least two substantially concentric ferrules, mechanically connected to each other.

The invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawings showing several embodiments of the wheel according to the invention. Figure 1a is a partial view in cross section through a plane passing through the axis of rotation of the wheel according to a first embodiment.

Figure 1b is an enlarged detail view of the wheel of Figure 1a. Figure 2a is a partial view in cross section through a plane passing through the axis of rotation of the wheel according to a second embodiment.

Figures 2b, 2c are detailed views on an enlarged scale of the wheel of Figure 2a.

Figure 3a is a partial view in cross section through a plane passing through the axis of rotation of the wheel according to a third embodiment.

Figure 3b is an enlarged detail view of the wheel of Figure 3a.

FIG. 3c is a side view on a reduced scale illustrating the arrangement of the reinforcement cables of the sidewalls "in tangents" to the wheel of FIG. 3a.

Figure 4a is a cross-sectional view through a plane passing through the axis of rotation of the wheel according to a fourth embodiment.

Figures 4b, 4c are detail views on an enlarged scale of the wheel of Figure 4a.

Figure 5a is a partial view in cross section through a plane passing through the axis of rotation of the wheel according to a fifth embodiment.

Figure 5b is an enlarged detail view of the wheel of Figure 5a.

Figures 6a and 6b are two partial views in cross section through a plane passing through the axis of rotation of the wheel according to a sixth embodiment.

According to a first embodiment shown in FIGS. 1a and 1b, the wheel 2, of median plane M is mounted on a hub 3, the assembly rotating around an axis of rotation R. The wheel 2 comprises a disc 4 connected to the hub 3 using a plurality of screws 5. The disc 4 has a central bore 6 making it possible to center it on the hub 3, this bore being visible in FIG. 4a.

The wheel 2 also includes a rim 7 fixed to the disc 4 by the welds 8. The wheel comprises a non-pneumatic casing 9 mounted on the rim 7 by means described below. Envelope 9 has a tread 10 bonded by its inner surface 12, to an annular part 13. The annular part 13 constitutes, in known manner, the inextensible belt of the envelope, of a rigidity adapted to the load to be transported.

The introduction of the casing 9 on the rim 7 is carried out in the direction symbolized by the arrow I.

The casing 9 also includes two flexible sidewalls called first sidewall 14 and second sidewall 15, the second sidewall 15 being located upstream of the first sidewall 14 in the direction of introduction I and therefore being introduced on the rim 7 after the first sidewall 14 These sidewalls 14, 15 connect the annular part 13 to the rim 7.

The two flanks 14, 15 have a frustoconical shape with an axis R, and are located on either side of the median plane M. The connection zones of the two flanks 14, 15 to the rim 7 are closer to the median plane M of the wheel 2 that the connection zones of the sidewalls 14, 15 to the annular part 13. The two sidewalls 14 and 15 have on their edge intended to be in contact with the rim 7 a circular bead. The first sidewall 14 has a first circular bead 16 and the second sidewall 15 has a second circular bead 17.

The second bead 17 has a circular bead 18, of diameter smaller than that of the rest of the bead 17 situated on its end intended to come into contact with the rim 7.

The rim 7 has on its outer face intended to receive the casing 9, a first flange 19, situated on its edge most downstream in the direction of introduction I. This first flange 19 is reinforced by a circular return 20.

Upstream of the first flange 19, the rim has a first seat 22 and a circular safety boss 23, coaxial with the wheel, on the seat 22, near the flange 19.

The rim 7 has on its outer face intended to receive the casing 9, on its edge most upstream in the direction of introduction I, a circular groove 24. This groove is limited downstream by an edge 25 connecting it to the second seat 26, and upstream by a second flange 27 of the rim 7 reinforced upstream by a circular return 28.

The first bead 16 bears radially on the first seat 22 and comes into abutment laterally on the flange 19, the boss 23 not impeding the establishment of the bead 16 during the mounting of the casing 9 on the rim, but improving its retention in position in contact with the flange 19 in the event of very high loads, for example in the event of rapid driving on a winding road.

The second bead 17 bears radially on the second seat 26, the heel 18 of this second bead 17 being housed in the groove 24 and held in position.

In this embodiment, the annular part 13 is composed, starting from the inner surface 12 of the tread, of the following superposed plies: - a calendered ply 29 made of steel cables, substantially parallel to each other, and inclined d 'an angle less than 10 ° relative to a plane perpendicular to the axis of rotation R,

a calendered sheet 30 made up of steel cables, substantially parallel to each other, and inclined at an angle of less than 10 ° relative to a plane perpendicular to the axis of rotation R, but opposite to that of the sheet 29, and,

- A calendered sheet 32 made of textile cables, substantially parallel to each other, and substantially perpendicular to a plane perpendicular to the axis of rotation R. On the other hand, in this embodiment the sides 14 and 15 consist of sheets following superimposed, between the inside and the outside of the envelope 9:

a first ply 33 of sidewall reinforcement cables 14, 15, not calendered in the area of the sides 14, 15, a first layer 34 of polytetrafluoroethylene known under the brand Teflon,

a second ply 35 of sidewall reinforcement cables 14, 15, not calendered in the area of the sidewalls 14, 15,

a second layer 34 of Teflon, a layer 36 of a mixture of elastomers intended to protect the sides 14, 15 from external aggressions such as for example ultraviolet rays, oxidation by oxygen and by ozone, shock during use.

Teflon has the desired properties of a material with a low coefficient of friction, stable in temperature and not adhering to mixtures of vulcanized elastomers. Each ply 33, 35 is made up of textile cables. These two plies 33 and 35 are crossed, the cables of the two plies 33 and 35 being arranged at an opposite angle relative to a meridian plane, respectively 45 ° and -45 ° in this embodiment. Each bead 16, 17 is formed by the partially turned end of a sidewall 14, 15, in the vicinity of the rim 7, around a ring 37 consisting of three steel wires 38 2mm in diameter, coated in a mixture of elastomers 39. The two beads 16 and 17 are surrounded by a layer of rubber 40. The heel 18 of the second bead 17, of diameter smaller than that of the rest of the bead 17 located on its end intended to come into contact with the rim 7 and upstream of the part intended to bear radially on the second seat 26, in the direction of introduction I, is formed in the rubber layer 40, and comprises a first reinforcement 42, consisting of the extension of the plies of cables 33, 35 of the sidewall 15, enveloping the heel 18. This first reinforcement guarantees the integrity of the heel 18, during assembly or disassembly operations. The heel 18 also includes a second reinforcement 43, consisting of a set of polyester threads arranged circularly and placed substantially in the center of the groove 24, which increases the resistance of the casing 9 on the rim 7, under force parallel to the axis R, for example in a bend.

In the beads 16, 17, the cables of the crossed plies 33 and 35 are interconnected by a mixture of elastomers and are obviously integral with the beads in which they are anchored by gluing.

According to a second embodiment shown in FIGS. 2a, 2b and 2c, the annular part 13 comprises two circular reinforcements 44, concentric with the wheel 2, respectively arranged in the zones of the annular part 13 furthest from the median plane M. A circular section 45 of a mixture of elastomers is interposed between each of the circular reinforcements 44 and the flexible flank 14, 15 corresponding in the zone of connection of the latter to the annular part 13. These reinforcements 44 together have a rigidity in bending total representing more than 10% of that of the annular part 13.

Reinforcement 44 can be produced in non-exclusive variants using:

- a profile, full or hollow, of a resin reinforced with glass or carbon fibers, arranged on its periphery or a hollow profile, - of a profile of a resin reinforced by glass fibers, or of another material, short and randomly distributed, or

- by overmolding a mixture of elastomers on a crown made up of several turns of a drawn wire of steel, with high elastic limit, of diameter close to 2.0 mm.

Outside the area of the flexible sidewalls 14, 15, that is to say in the areas of the beads 16 and 17, and in the areas of connection of the sidewalls 14, 15 to the annular part 13, the plies 33 and 35 are bonded to each other, either directly or by means of a mixture of elastomers 46, as it appears in Figures 2b and 2c.

On the other hand, in this embodiment, the two flanks 14, 15 are here completely independent of one another: in this exemplary embodiment, on either side of the median plane M, the flanks 14, 15 have a circular extension 47 of a few centimeters, embedded in the annular part 13, in the area of connection of the sides 14, 15 to the annular part 13, and held by gluing.

According to a variant not shown, the teflon layers 34 can be replaced by an anti-sticking agent with a low coefficient of friction, based on silicones for example. According to a variant not shown, it is also possible to use, in the area of the sides, plies of calendered cables but not glued to each other. In this case, in the sidewall area, a thin sheet of teflon, a few tenths of a mm thick, is interposed between the cable plies, aimed at reducing the losses due to the hysteresis of the mixture of elastomers, and transferring as much as possible the transmission of forces directly to the cables themselves, thus avoiding passing them through the mixture of elastomers.

According to a third embodiment shown in FIGS. 3a, 3b and 3c, the flexible sides 14, 15 are reinforced in a particular way, called "arrangement in tangents". The arrangement of the polyester cables 48 is shown in Figure 3c.

Each cable 48, in the region of the flexible flank 14, 15 considered, projects onto a plane perpendicular to the axis of rotation R according to a segment substantially tangent to a circle concentric with the rim 7, the diameter of which is equal to that of the seat 22, 26 considered from rim 7, increased by approximately 10 mm in this embodiment, depending on the architecture of the bead 16, 17 considered.

This cable 48 is also wound around the rim 7 in a winding zone 49 corresponding to an angular portion of angle t equal to 60 ° in the embodiment.

The angle t can vary from 0 ° to “n” times 360 °, “n” possibly being greater than one in variants not shown. The parts of the cable situated outside this winding zone 49 are substantially rectilinear and join the annular part 13 at points X and Y. At these points X and Y, the cable is extended, in the direction of the median plane M and is glued on, or in, the annular part 13, as it appears in FIG. 3a.

According to a variant not shown, this same cable can be extended and come out at the corresponding point on the other side, and be arranged on this side, as described above to reinforce it, before returning in the same way to the previous side. The reinforcement of the two sides can thus be carried out with a single cable, without any interruption, by repeating the operations described above.

The cables 48, in the area of the flanks 14, 15, are coated with a teflon sheath 50, and do not adhere to the outer protective layer 36. It appears that if the angle t is greater than 20 ° or 30 °, depending on the loads transported and depending on the speed of the vehicle, the arrangement of the reinforcement cables 48 in the winding zones 49, close to the rim 7, replaces the ring 37 described above by allowing the beads 16, 17 to be stiffened. The tangent arrangement of the sidewall reinforcements makes it possible to achieve a high load capacity of the non-pneumatic envelope, without degrading the rolling resistance.

According to a variant, the cables made of textile material can be replaced by metal cables. According to a variant, only part of the cables for reinforcing the flexible sides can be produced according to the arrangement in tangents, the others being, for example, using crossed plies.

According to a variant, the cables 48 are replaced by unitary polyamide wires, with a diameter close to 1 mm, covered with a layer 50 of teflon a few hundredths of a mm thick. According to a variant, the layer 50 of a material with a low coefficient of friction and nonadherent, is obtained by a direct physicochemical treatment of the surface of the wires constituting the cables 48 by deposition under cold plasma of a thin layer of graphite a few microns thick. According to another variant, the physico-chemical treatment consists in modifying the crystallization rate of the polymer of the material composing the reinforcement by surface heat treatment.

The physico-chemical treatments described in the last two variants create a surface layer 50 of a few microns thick, the friction and adhesion characteristics of which are those desired, without harming the overall resistance of the cable or wire.

FIGS. 4a, 4b, 4c represent a fourth embodiment close to the first mode making it possible to illustrate the positioning of the casing 9 on the rim 7, this figure in fact representing the casing 9 during mounting on the rim 7. In this embodiment, the following diameters, considered with respect to the axis of rotation R, are used for the elements of the outer face of the rim 7, and allow the casing 9 to be placed on the rim 7: the diameter D5 of the flange 19 is 471 mm, the diameter D4 of the first seat 22 and of the second seat 26 is 444 mm, the diameter D3 of the safety boss 23 is 449 m, the diameter D2 of the bottom of the circular groove 24 is 432 mm, the diameter D1 of the second flange 27 is 450 mm, slightly greater than D4.

The second flange 27, of a diameter greater than that of the seats 22 and 26, can be crossed, during assembly, by the two beads 16, 17 due to the proximity of the groove 24 and the elasticity of the casing 9 and in particular that of the rubber 40, located on the part of the beads 16, 17 in contact with the rim 7.

The angle Φ of the slope of the surface of revolution connecting the groove 24 and the second flange 27, measured from the axis of rotation R, is 70 ° in this embodiment.

The casing 9 is first engaged and placed on one side A of the wheel 2, the first bead 16 being positioned on the first seat 22, bearing against the flange 19, and the second bead 17 being positioned on the second seat 26 with the heel 18 placed in the groove 24. At this time, on the side B of the wheel 2 diametrically opposite to A, the casing 9 is not in the assembled position. To complete the assembly, apply to near the end of the heel 18 a force represented by the arrow F, directed from the outside towards the inside of the casing 9, of a few hundred Newton, and obtain that the latter deforms enough to engage above the rim 27, and fits naturally in the groove 24. An opening 52 is formed in the heel 18 between the groove 24 and the heel 18. Two other openings 52 have been made in the two half-planes distant from 12 ° angle in rotation relative to the axis R and located on either side of the half-plane of Figure 4b. These openings 52 allow the introduction of levers bearing on the second flange 27 and then on the return 28 to take out the heel 18 from the groove 24, and thus disassemble the casing 9 from the rim 7, when it is changed for wear , or its temporary replacement with winter tires.

According to a fifth embodiment shown in Figures 5a and 5b, the rim 7 made of cast aluminum and machined aluminum is removable in two parts 53 and 54 connected by screws 55, the disc 4, integral with the part 54, being fixed on the hub 3.

Each sidewall 14, 15 is embedded and glued in an annular piece forming the bead 16, 17, made of a polyamide-type resin reinforced by cables 56 arranged in a circular pattern. Each of the two beads 15, 16 is supported on one of the two hooks 57 of the rim 7, in a frustoconical area, these two hooks 57 maintaining the required tension in the sidewalls 14, 15. A cylindrical spacer 58 makes it possible to increase the pressure exerted by the two beads 16, 17 on the hooks 57. This has the effect of increasing the capacity of the wheel 2 to transmit high engine or braking torques.

According to a sixth embodiment, shown in Figures 6a and 6b, the casing 9 is shown mounted on the rim in Figure 9b and not mounted in Figure 9a.

The tread 10 is generally toroidal in shape. The annular part 13 is composed of two ferrules: a first ferrule 59 of toroidal shape, and a second ferrule 60 of smaller diameter and of cylindrical shape, the two ferrules 59, 60 being connected by radial parts 62.

The ends of each sidewall 14, 15 are wound and glued on two circular beads 16, 17. The rim 7, the outer face of which is symmetrical with respect to the median plane, has two hooks 57 in shape of an inverted rim, thus forming a housing 64 intended to receive a bead 16, 17.

The edges 63 of the ferrule 59 can deform elastically, their equilibrium position shown in FIG. 6a, being such that the beads 16, 17 are spaced apart from each other by a distance greater than the width of the rim 7. These beads 16, 17 are made of a mixture of hard elastomer but deformable enough to be engaged above the hooks 57 of the rim 7, the diameter of which is greater than that of the beads 16, 17. The setting in place of the two beads 16, 17 between the two hooks 57 causes a deformation of the two edges 63, which then push each bead 16, 17, through the sidewall 14, 15, corresponding in its housing 64 inside the 'hooking 57. The residual elasticity of the edges 63 then gives the sides 14, 15 the required tension preload. The invention is not limited to the embodiments described, on the contrary it embraces all variants. Thus, in particular, the means of attachment to the rim can have different shapes and use, for example, other types of removable rim.

Claims

1. Vehicle wheel (2) comprising a rim (7) connected directly or by means of a disc (4) to a hub (3) of the vehicle and a non-pneumatic casing (9) comprising:

- a tread (10) of generally cylindrical or toric shape,

an annular part (13), constituting the inextensible belt of the non-pneumatic envelope (9), fixed to the tread (10), radially inside the latter, and

- two flexible sides (14, 15) of frustoconical shape connecting the annular part (13) to the rim (7), characterized in that each side (14, 15) comprises plies (33, 35) of cables (48) or reinforcing wires, each cable (48) or wire being separated from the other components of the wheel (2) by at least one layer (34, 50) of a material with a low coefficient of friction and not adhering to the others components of the wheel (2),

a layer (50) of this material being placed individually on each cable or wire, or constituted by a physicochemical treatment of the surface of the cables (50) or of the reinforcement wires, and / or

- A layer (34) of this material being disposed between the plies (33, 35) of neighboring cables or wires and between the cable plies (33, 35) or wires and the mixtures of elastomers or other components of the wheel (2) surrounding.

2. Wheel (2) according to claim 1, characterized in that the flexible sidewalls (14, 15) comprise at least two plies (33, 35) of cables (48) or crossed wires, calendered or non-calendered, as well as a protective layer (36), in particular produced from elastomers, situated on the outside of the envelope, and in that a layer (34) of the material with low coefficient of friction is placed between two plies (33, 35) of adjacent cables or wires and between the protective layer (36) and the ply (33) of adjacent cables or wires of the protective layer (36).

3. Wheel (2) according to one of claims 1 and 2, characterized in that at least part of the cables (48) or sidewall reinforcement wires (14, 15) projects on a plane perpendicular to the axis of rotation (R) of the wheel (2) according to straight line segments substantially tangent to a circle, concentric with the rim (7), of diameter greater than the part of the rim 7 called seat (22, 26) on which the sidewall (14, 15) bears radially.

4. Wheel (2) according to one of claims 1 to 3, characterized in that the annular part (13) comprises two lateral circular reinforcements (44) whose rigidity in total bending, that is to say of the two reinforcements (44) considered together, represents at least 10% of that of the annular part (13), the bending axis considered being parallel to the axis of rotation (R) of the wheel (2) and located in the vicinity of the center of gravity of the section of the annular part (13), each of them being connected to the annular part (13) and disposed near the zone of connection of one of the two flexible sides (14, 15) with it this.

5. Wheel (2) according to one of claims 1 to 4, characterized in that the connection of the sidewalls (14, 15) to the rim (7) imposes a prestress in tension of the sidewalls (14, 15).

6. Wheel (2) according to one of claims 1 to 5, characterized in that the connection zones of the two sides (14, 15) to the rim (7) are closer to the median plane (M) of the wheel (2) that the areas of connection of the sidewalls (14, 15) to the annular part (13), and in that each sidewall (14, 15) has, on its edge intended to be in connection with the rim (7 ), a non-extendible circular bead (16, 17), the two beads (16, 17) being held in position by corresponding hooking means (57, 19, 23, 24, 27, 58, 64) located on the rim (7) at two locations separated by a distance less than the resting distance of the two beads (16, 17), thereby creating the required tension preload of the sidewalls (14, 15).

7. Wheel (2) according to claim 6, characterized in that the rim (7) is removable in several parts (53, 54, 58) allowing the establishment of the beads (16, 17) of the casing (9 ) on the attachment means (57, 58).

8. Wheel (2) according to claim 6, characterized in that the attachment means comprise: - on a first location located on the edge of the rim (7) on the side opposite to the side of introduction of the casing ( 9) on the rim (7), a first flange (19) of diameter greater than the diameter of the first circular bead (16) and constituting a lateral stop for the first bead (16) simultaneously pressing on the first seat (22) of the rim (7), and, - on a second location located on the edge of the rim (7) on the side of the introduction, an annular groove (24), of minimum diameter less than the diameter of the second seat (22, 26) of the rim (7), in which is housed a flexible annular heel (18) formed on the edge of the second bead (17) allowing the latter to be held in position, the groove (24) being delimited upstream in the direction of introduction by a second rim (27) of the rim (7), of diameter close to the diameter of the second bead (17) and allowing the passage of the two bead (16,17) during the mounting of the casing (9) on the rim (7) .

9. Wheel (2) according to claim 8, characterized in that at least one circular safety boss (23) is formed on the outer surface of the rim (7) between one of the support seats (22, 26) of one of the beads (16, 17) and the median plane (M), the maximum diameter of this boss being slightly greater than that of the seat (22, 26).

10. Wheel (2) according to one of claims 8 and 9, characterized in that the heel (18) is made of an elastic material and reinforced by elastic cables (43) arranged circularly.

11. Wheel (2) according to one of claims 8 to 10, characterized in that the maximum slope Φ of the surface of revolution connecting the bottom of the groove (24) to the second flange (27), angle measured from the axis of rotation of the wheel, is greater than 45 °.

12. Wheel (2) according to one of claims 1 to 11 characterized in that the annular part (13) consists of at least two ferrules (59, 60) substantially concentric, mechanically connected together.