Wheel rim for an extraterrestrial vehicle and wheel

Abstract

The invention relates to a wheel rim (100) having an axis of rotation (X1-X1) and comprising an attachment hub (110) intended to be attached to the vehicle, two flanges (120), each attached to the attachment hub (110), and a shroud (140) attached to each of the flanges (120). Each flange comprises a frustoconical body (121) axially bounded by a small-diameter end (122) and a large-diameter end (123) located on the side opposite the attachment hub and connected to a lateral end (144, 145) of the shroud. The frustoconical body of each flange comprises at least a first series (130) of internal grooves (131) extending axially from the small-diameter end towards the large-diameter end over a length at least equal to 10% of the length of the generatrix of the frustoconical body.

Description

[0001] DESCRIPTION

[0002] TITLE: Wheel rim for an extraterrestrial vehicle and wheel.

[0003] Technical field of the invention

[0004] The present invention relates to the field of a rim of a wheel intended to equip an extraterrestrial exploration vehicle, intended to move, for example, on the moon or on the planet Mars, in an environment subject to very strong temperature variations, which can reach very low temperatures down to -243°C and very high temperatures up to +130°C. Such a thermal gradient is notably measured at the South Pole of the moon.

[0005] State of the prior art

[0006] Metal rims were made to equip extraterrestrial vehicles.

[0007] However, known rigid metal rims cannot withstand a thermal gradient in the above-mentioned temperature range.

[0008] Indeed, when using known rigid metal rims in an environment subject to very strong temperature variations, the different parts of the wheel can undergo differentiated thermal expansions, which generates strong stresses, in particular at the connection between these different parts. Stresses greater than the elastic limit of some of the parts constituting the rim are observed, which is not structurally supportable.

[0009] Thus, there is a need to address the above-mentioned drawbacks.

[0010] Statement of the invention

[0011] The inventors aim to design a rim for a wheel that is both rigid and capable of withstanding an extraterrestrial environment, in a temperature range that can go from very low temperatures to very high temperatures, typically in the interval [-243°C; + 130°C], while being lightweight. The present invention relates to a rim for a wheel of a vehicle, in particular an extraterrestrial vehicle, having an axis of rotation and comprising, as elements of revolution around said axis of rotation, and radially from the inside to the outside, a fixing hub intended to be fixed to the vehicle, two discs or flanges each fixed to the fixing hub and a ferrule fixed to each of the flanges.

[0012] In other words, said ferrule radially surrounds the fixing hub and the flanges.

[0013] Each flange comprises a truncated body, generally shaped like a hollow truncated cone, extending axially inside the ferrule and delimited axially by a small diameter end connected to the fixing hub and a large diameter end located on the side opposite the fixing hub, and connected to the lateral ends of the ferrule.

[0014] The frustoconical body of each flange comprises at least a first series of internal grooves extending axially from the small diameter end towards the large diameter end over a length at least equal to 10% of the total length of the generatrix of the frustoconical body.

[0015] For example, the first series of internal grooves extends axially from the small diameter end towards the large diameter end over a length preferably at most equal to 90%, preferably at most equal to 40%, of the total length of the generatrix of the frustoconical body. Such a rim makes it possible to reduce the stresses linked to the thermomechanical cycles of the rim, during temperature variations.

[0016] The internal grooves made in the truncated body of each flange make it possible to absorb the expansion of the ferrule at the connection between the flange and said ferrule and the expansion of the flange itself at its connection with the fixing hub and to maintain a mechanical stress lower than 30% of the elastic limit (or the plasticity threshold) when the flanges are made of thermoplastic materials. Furthermore, the length of the internal grooves makes it possible to give good flexibility to the fixing hub.

[0017] Advantageously, the two flanges are identical to each other.

[0018] Advantageously, the first series of internal grooves comprises a plurality of internal grooves circumferentially, preferably regularly, spaced from each other, two adjacent internal grooves delimiting an internal blade, each internal blade comprising at least one axial bore allowing the flange to be fixed to the fixing hub.

[0019] Preferably, the internal grooves are made in the thickness of each flange. Consequently, they open onto the internal surface and the external surface of the truncated body.

[0020] For example, each internal groove of the first series of grooves comprises a main part having a width, that is to say the dimension considered in the circumferential direction, substantially constant at least equal to 1 mm and at most equal to 5 mm, preferably at most equal to 1.5 mm, and an end part, for example of flared shape, having a width greater than the width of the main part.

[0021] The wider end portion than the main portion of each internal groove helps to limit localized stress concentrations. The width of the internal grooves allows the torsional stiffness of the flange to be modified by modifying the width of the remaining material, i.e. the internal blades.

[0022] Preferably, the major portion of each internal groove extends from the small diameter end over at least 70% to at most 90% of its length.

[0023] For example, the shape of the end part is non-angular, such as, for example, a drop of water, an oval, an ellipse.

[0024] According to one embodiment, the frustoconical body of each flange comprises a second series of external grooves extending axially from the large diameter end towards the small diameter end over a length at least equal to 10% of the length of the generatrix of the frustoconical body. For example, the second series of external grooves extends axially over a length at most equal to 90%, preferably at most equal to 40% of the length of the generatrix of the frustoconical body.

[0025] The combination of the first set of internal grooves and the second set of external grooves helps to absorb the effects of thermal expansion.

[0026] Furthermore, the second series of external grooves makes it easier to produce the flanges by coning the discs through mechanical deformation.

[0027] Advantageously, the second series of external grooves comprises a plurality of external grooves circumferentially, preferably regularly, spaced from each other, two adjacent external grooves delimiting an external blade, each external blade comprising at least one radial bore for fixing the flange to the ferrule.

[0028] For example, the external grooves are made in the thickness of each disc. Consequently, they open onto the internal surface and the external surface of the truncated body.

[0029] According to a non-limiting embodiment, the external grooves of the second series of grooves are arranged in a staggered pattern relative to the internal grooves of the first series of grooves.

[0030] This allows for longer grooves without weakening the central part of each flange. In this case, a total groove length of up to 90% of the total length of the truncated body is obtained.

[0031] Preferably, the outer grooves of the second series of grooves are spaced a non-zero axial distance apart from the inner grooves of the first series of grooves.

[0032] Without limitation, the end portion of the inner grooves of the first series of grooves does not extend beyond the end portion of the outer grooves of the second series of grooves.

[0033] Alternatively, it could be provided that the external grooves of the second series of grooves are extended by the internal grooves of the first series of grooves, so as to form only one series of grooves extending over a length equal to the total length of the generatrix of the frustoconical body.

[0034] Alternatively, any other arrangement could be provided for the external grooves of the second series and the internal grooves of the first series.

[0035] Advantageously, each external groove comprises a main part having a width, that is to say the dimension considered in the circumferential direction, substantially constant at least equal to 1 mm and at most equal to 5 mm, preferably at most equal to 1.5 mm, and an end part, for example of flared shape, having a width greater than the width of the main part, the main part of each external groove extending from the large diameter end over at least 70% to at most 90% of its length.

[0036] The wider end portion than the main portion of each external groove helps to limit localized stress concentrations.

[0037] For example, the shape of the end portion of each outer groove is non-angular, such as, for example, a water drop, an oval, an ellipse.

[0038] The width of the external grooves allows the torsional stiffness of the flange to be modified by modifying the width of the remaining material, i.e. the external blades.

[0039] For example, each flange has a number of internal grooves ranging from thirty to seventy-two.

[0040] For example, each flange has a number of external grooves ranging from thirty to seventy-two.

[0041] Advantageously, each flange further comprises a plurality of radial fixing tabs extending radially from the small diameter end inwards, i.e. towards the axis of rotation for fixing the flange to the fixing hub and a plurality of axial fixing tabs extending from the large diameter end axially outwards, on the side opposite the small diameter end for fixing the flange to the ferrule. In other words, the flanges are assembled together via the fixing hub.

[0042] For example, each radial fixing tab comprises at least one axial drilling intended to cooperate with a corresponding axial drilling made on the fixing hub for fixing the flange with fixing means.

[0043] The number of axial holes is preferably equal to the number of axial holes of the fixing hub.

[0044] For example, each axial fixing tab comprises at least one radial drilling intended to cooperate with a corresponding radial hole made on the ferrule for fixing the flange with fixing means.

[0045] The number of radial holes is preferably equal to the number of radial holes in the ferrule.

[0046] For example, the small diameter end of the frustoconical body of each flange has an external diameter preferably equal to 230 mm.

[0047] For example, the large diameter end of the frustoconical body of each flange has an external diameter preferably equal to 397 mm.

[0048] For example, the frustoconical body of each flange comprises a thickness, that is to say the dimension considered in a direction perpendicular to the direction of extension of the frustoconical body, at least equal to 0.5 mm and at most equal to 5 mm, for example equal to 0.75 mm.

[0049] For example, the truncated body of each flange includes a total length, that is to say the dimension considered in the direction of extension of the truncated cone, for example equal to 147.5 mm.

[0050] According to one embodiment, the fixing hub comprises an annular base, preferably substantially planar, comprising a plurality of axial holes intended to cooperate with fixing means, for example screws / nuts or rivets, for fixing to the flanges.

[0051] Advantageously, the fixing hub further comprises a plurality of fixing lugs extending radially from the base towards the axis of rotation of the rim, each fixing lug comprising at least one axial bore intended to cooperate with centering means, for example screws / nuts or rivets, for fixing to the vehicle.

[0052] For example, the fixing lugs are circumferentially regularly distributed on the radially inner surface of the fixing hub base.

[0053] For example, and in no way limiting, the attachment hub includes six attachment lugs. Generally, the attachment hub includes at least two attachment lugs for attachment to the extraterrestrial vehicle.

[0054] For example, the fixing hub has a thickness, that is to say the dimension taken in the axial direction, at least equal to 1 mm and at most equal to 10 mm. This makes it possible to limit the mass of the fixing hub.

[0055] The outer diameter of the mounting hub depends on the dimensions of the flanges. For example, the outer diameter of the mounting hub is between 235 mm and 260 mm.

[0056] According to one embodiment, the ferrule comprises a body of generally hollow cylindrical shape comprising a thickness, that is to say the dimension taken in the radial direction, at least equal to 0.5 mm and at most equal to 5 mm, preferably equal to 0.75 mm, the ferrule comprising a plurality of radial holes made at each lateral end of the ferrule and each intended to cooperate with a radial drilling made in the flange and fixing means, for example screws / nuts or rivets, for fixing on the flanges.

[0057] The body of the ferrule is, for example, delimited radially by an internal surface and an external surface and axially by two opposite lateral surfaces.

[0058] The outer diameter and axial distance of the ring depends on the tire dimensions. For example, the outer diameter of the ring is 398.5 mm for an axial distance of 300 mm.

[0059] In the assembled position, the ferrule radially surrounds the fixing hub and the discs, so that no element extends axially beyond the lateral surfaces of the ferrule. In a non-limiting manner, the rim is symmetrical with respect to a plane passing through the axis of rotation and with respect to a median plane of the ferrule perpendicular to the axis of rotation.

[0060] The two truncated bodies may or may not be identical.

[0061] It would also be possible to provide a geometry of the grooves that is not symmetrical from one flange to the other.

[0062] Advantageously, the fixing hub, the ferrule, and the flanges are made of a metallic material included in the group comprising aluminum, copper, stainless steel or titanium or of a thermoplastic material compatible with ultra-high vacuum included in the group comprising polyetheretherketone (PEEK), polyetherimide (PEI) or polyimide (PI).

[0063] For example, aluminum is 5086, A6061-T6 or A6063-T6 aluminum.

[0064] For example stainless steel is AISI 304L, 304LN, 316L, 321, 347.

[0065] Preferably, the fixing hub is made of a material different from the material of the ferrule and flanges. For example, the fixing hub is made of a low-expansion material to have a more consistent tightening of the nuts, preferably titanium.

[0066] The flanges and the ferrule are preferably made of aluminum.

[0067] According to another aspect, the invention relates to a mounted assembly or wheel comprising a rim as described above and an airless tire mounted on said rim.

[0068] Advantageously, the airless tire comprises, radially from the inside to the outside, a supporting structure, intended to cooperate with the rim, a shear band and a tread, the supporting structure comprising a plurality of circumferentially regularly distributed spokes fixed to the rim by fixing means, said fixing means being configured to fix both a spoke of the tire and the rim at the radial holes made on the flanges and the radial holes made on the ferrule. The pitch of the external grooves may be dependent or independent of the number of spokes of the tire. The fixing means make it possible to fix both a spoke and an external blade of the flanges of the rim.

[0069] For example, at least the supporting structure and the shear band are each made of at least one material having the following mechanical characteristics, measured according to ASTM D638 of ASTM (“American Society for Testing and Materials”) International:

[0070] - Young's modulus in tension E, measured at a temperature equal to 20°C, at least equal to 1 GPa and at most equal to 6 GPa, and, measured at a temperature equal to - 196°C, at least equal to 1.2 GPa and at most equal to 9 GPa, and

[0071] - a maximum tensile stress Sm, measured at a temperature equal to 20°C, at least equal to 25 MPa and at most equal to 150 MPa, and, measured at a temperature equal to - 196°C, at least equal to 40 MPa and at most equal to 260 MPa.

[0072] Brief description of the drawings

[0073] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0074] [Fig. 1] represents an overall perspective view of a mounted assembly or wheel comprising a rim according to one embodiment of the invention and an airless tire;

[0075] [Fig.2] illustrates in perspective the rim according to figure 1;

[0076] [Fig.2A] is an exploded view of Figure 2;

[0077] [Fig.3] is a side view of the rim of Figure 2; [Fig.4] is a sectional view of the rim along section plane IV-IV of Figure 3;

[0078] [Fig.5] illustrates a disc of the rim of Figure 2; and

[0079] [Fig.5A] is a detail of Figure 5.

[0080] Detailed description of at least one embodiment

[0081] In the following description, the terms "circumferential", "axial" and "radial" are defined relative to the axis of rotation XI - XI of the rim 100.

[0082] The “circumferential” direction designates a direction in a plane perpendicular to the axis of rotation X l -Xl of the rim 100 and tangent to the tread, the “axial” direction is the direction of the axis of rotation Xl -Xl of the rim 100 and a “radial” direction designates a direction perpendicular to the axis of rotation Xl -Xl of the rim 100.

[0083] Figure 1 is an overall perspective view of a mounted assembly or wheel 10 comprising a rim 100 and a tire 1 mounted on said rim 100.

[0084] The 100 rim is intended to equip an extraterrestrial vehicle wheel and is capable of withstanding strong temperature gradients ranging from -243°C to +130°C.

[0085] By “rim” is meant a structure connecting to the vehicle and centrally supporting the tire 1.

[0086] The rim 100 comprises, as elements of revolution around said axis of rotation Xl -Xl, and radially from the inside to the outside, a fixing hub 110 ensuring the connection with the vehicle, two discs or flanges 120 each fixed to the fixing hub 110 and a ferrule 140 fixed to each of the flanges 120.

[0087] The attachment hub 110 forms the attachment interface between the wheel 10 and the vehicle.

[0088] The fixing hub 110 comprises an annular base 111, here substantially planar, comprising a plurality of axial holes 112 intended to cooperate with fixing means (not shown), for example screws / nuts or rivets, for fixing on the flanges 120.

[0089] The fixing hub 110 further comprises a plurality of fixing lugs 113 extending radially from the base 111 towards the axis of rotation Xl-Xl of the rim 100. Each fixing lug 113 comprises an axial bore 114 intended to cooperate with centering means (not shown), for example screws / nuts or rivets, for fixing to the extraterrestrial vehicle.

[0090] The fixing lugs 1 13 are, here, circumferentially regularly distributed on the radially inner surface of the base 1 1 1 of the fixing hub 1 10.

[0091] As illustrated, and in no way limiting, the attachment hub 110 comprises six attachment tabs 113. Generally, the hub 110 comprises at least two attachment tabs 113 for attachment to the extraterrestrial vehicle.

[0092] The thickness eno of the fixing hub 1 10, here the dimension taken in the radial direction, is between 1 mm and 10 mm, in order to limit the mass of the fixing hub 1 10.

[0093] The outer diameter D uo of the fixing hub 1 10 depends on the dimensions of the flanges 12.

[0094] For example, the outer diameter D uo of the fixing hub 1 10 is between 235 mm and 260 mm.

[0095] The ferrule 140 comprises a body 141 of generally hollow cylindrical shape delimited radially by an internal surface 142 and an external surface 143 and axially by two opposite lateral surfaces 144, 145.

[0096] The body 141 comprises a thickness ei40, here the dimension taken in the radial direction, between 0.5 mm and 5 mm, preferably equal to 0.75 mm.

[0097] The outer diameter and the axial length or distance of the ferrule 140 depend on the dimensions of the tire 1. For example, the outer diameter of the ferrule 140 is equal to 398.5 mm for an axial length of 300 mm. Each lateral end of the ferrule 140 comprises a plurality of radial holes 146 each intended to cooperate with fixing means (not shown), for example screws / nuts or rivets, for fixing to the flanges 120.

[0098] In the assembled position, the ferrule 140 radially surrounds the fixing hub 110 and the flanges 120, so that no element extends axially beyond the lateral surfaces 144, 145 of the ferrule 140.

[0099] In a non-limiting manner, the rim 100 is, here, symmetrical with respect to a plane passing through the axis of rotation Xl-Xl and with respect to a median plane of the ferrule 140 perpendicular to the axis of rotation Xl-Xl. Alternatively, it could be provided that the rim 100 is not symmetrical with respect to a median plane of the ferrule 140 perpendicular to the axis of rotation Xl-Xl.

[0100] The 120 flanges are, here, identical to each other.

[0101] Alternatively, it could be provided that the flanges 120 are not identical in terms of dimensions.

[0102] Each flange 120 comprises a truncated body 121 of general shape in the form of a hollow truncated cone extending axially inside the ferrule 140.

[0103] The truncated body 121 is axially delimited by a small diameter end 122 and a large diameter end 123.

[0104] The flanges 120 are assembled together by means of the fixing hub 110.

[0105] In the assembled position, the small diameter end 122 of each flange 120 is located towards the fixing hub 110 while the large diameter end 123 of each flange 120 is located at the lateral ends 144, 145 of the ferrule 140, on the side opposite the fixing hub 110.

[0106] Each flange 120 further comprises a plurality of radial fixing tabs 124 for fixing to the fixing hub 110 and a plurality of axial fixing tabs 125 for fixing the flange 120 to the ferrule 140. The radial fixing tabs 124 extend from the small diameter end 122 radially inwards, i.e. towards the axis of rotation Xl-Xl.

[0107] Each radial fixing tab 124 comprises, here, an axial bore 126 intended to cooperate with a corresponding axial bore 112 made on the annular base 111 of the fixing hub 110 for fixing with fixing means. Alternatively, it could be provided that each radial fixing tab 124 comprises a number of axial bores 126 greater than or equal to two. The number of axial bores 126 is equal to the number of axial bores 112 of the fixing hub 110.

[0108] The axial fixing tabs 125 extend from the large diameter end 123 axially outwardly, on the side opposite the small diameter end 122.

[0109] Each axial fixing tab 125 comprises, here, a radial drilling 127 intended to cooperate with a corresponding radial hole 146 made on the ferrule 140 for fixing the flange 120 with fixing means.

[0110] Alternatively, it could be provided that each axial fixing tab 125 comprises a number of radial holes 127 greater than or equal to two. The number of radial holes 127 is equal to the number of radial holes 146 of the ferrule 140.

[0111] By way of non-limiting example, the small diameter end 122 has an external diameter D122 preferably equal to 230 mm.

[0112] The large diameter end 123 has, for example, an external diameter D123 preferably equal to 397 mm.

[0113] The thickness of the truncated body 121 of each flange 120, that is to say the dimension considered in a direction perpendicular to the direction of extension of the truncated cone, is, for example, between 0.5 mm and 5 mm, for example equal to 0.75 mm.

[0114] The total length L121 of the generatrix of the frustoconical body 121 of each flange 120, that is to say the dimension considered in the direction of extension of the frustoconical body, is, for example, equal to 147.5 mm. As illustrated in the figures, the frustoconical body 121 of each flange 120 comprises a first series 130 of internal grooves 131 extending axially from the small diameter end 122 towards the large diameter end 123 over a length Lu i at least equal to 10% of the length L121 of the generatrix of the frustoconical body.

[0115] For example, the first series 130 of internal grooves 131 extends axially over a length Lu i at most equal to 90%, preferably at most equal to 40% of the length Lui of the generatrix of the truncated body (121).

[0116] The length Lui of the internal grooves 131 makes it possible to provide good flexibility to the fixing hub 1 10.

[0117] The first series 130 of grooves comprises a plurality of internal grooves 131 circumferentially regularly spaced from each other. Two adjacent internal grooves 131 circumferentially delimit an internal blade 128.

[0118] Each internal blade 128 comprises at least the axial drilling 126 for fixing the flange 120 to the fixing hub 110.

[0119] The internal grooves 131 are, here, made in the thickness of each flange. Consequently, they open onto the internal surface and the external surface of the truncated conical body 121.

[0120] Each internal groove 131 comprises a main part 132 having a width W132, that is to say the dimension considered in the circumferential direction, substantially constant, between 1 mm and 5 mm, preferably between 1 mm and 1.5 mm, and an end part 133, of different shape, for example flared, having a width W133 greater than the width W132 of the main part 132.

[0121] The shape of the end portion 133 of each internal groove 131 here represents a drop of water. Alternatively, a different shape could be provided for the end portion 133, such as, for example, an oval, elliptical, or any other non-angular shape. The end portion 133 wider than the main portion 132 of each internal groove 131 makes it possible to limit localized stress concentrations.

[0122] The main portion 132 of each internal groove 131 extends from the small diameter end 122 over at least 70% to at most 90% of its length Lu i .

[0123] The width W 132, W 133 of the internal grooves 131 makes it possible to modify the torsional stiffness by modifying the width of the remaining material, i.e. of the internal blades 128 of the disc.

[0124] For example, each flange 120 comprises a number of internal grooves 131 between 30 and 72.

[0125] As illustrated in the figures, and in a non-limiting manner, the frustoconical body 121 of each flange 120 comprises a second series 135 of external grooves 136 extending axially from the large diameter end 123 towards the small diameter end 122 over a length L136 at least equal to 10% of the length L121 of the generatrix of the frustoconical body (121).

[0126] For example, the second series 135 of external grooves 136 extends axially over a length L136 at most equal to 90%, preferably at most equal to 40% of the length L121 of the generatrix of the frustoconical body 121.

[0127] Alternatively, it could be provided that the truncated body 121 of each flange 120 only comprises the first series 130 of internal grooves 131.

[0128] The second series 135 of external grooves 136 comprises a plurality of external grooves 136 circumferentially regularly spaced from each other. Two adjacent external grooves 136 circumferentially delimit an external blade 137.

[0129] Each external blade 137 comprises at least one radial bore 127 for fixing the flange 120 to the ferrule 140.

[0130] The external grooves 136 are, here, made in the thickness of each disc. Consequently, they open onto the internal surface and the external surface of the truncated cone. Each external groove 136 comprises a main part 138 having a width W138, that is to say the dimension considered in the circumferential direction, substantially constant between 1 mm and 5 mm, preferably between 1 mm and 1.5 mm, and an end part 139 of different shape having a width W139 greater than the width W138 of the main part 138.

[0131] The shape of the end portion 139 of each external groove 136 here represents a drop of water. Alternatively, a different shape could be provided for the end portion 139, such as, for example, an oval, elliptical, or any other non-angular shape.

[0132] The end portion 139 wider than the main portion 138 of each external groove 136 makes it possible to limit localized stress concentrations.

[0133] The main portion 138 of each outer groove 136 extends from the large diameter end 123 over at least 70% to at most 90% of its length L136.

[0134] The width of the external grooves 136 makes it possible to modify the torsional stiffness by modifying the width of the remaining material, i.e. the external blades 137.

[0135] For example, each flange 120 comprises a number of external grooves 136 between 30 and 72.

[0136] The combination of the first series of internal grooves 131 and the second series of external grooves 136 makes it possible to absorb the effects of thermal expansion.

[0137] Furthermore, the second series of external grooves makes it easier to taper the flanges 120 by mechanical deformation.

[0138] As illustrated, and in a non-limiting manner, the external grooves 136 of the second series 135 are arranged in a staggered manner relative to the internal grooves 131 of the first series 130. This makes it possible to obtain longer grooves without weakening the central part of each flange 120. In this case, a total length of grooves 131, 136 is obtained which can be up to 90% of the curvilinear length of the frustoconical body 121. The internal grooves 131 of the first series of grooves 130 are, here, spaced apart by a non-zero axial distance relative to the external grooves 136 of the second series of grooves 135.

[0139] As illustrated, and in a non-limiting manner, the end portion 133 of the internal grooves 131 of the first series of grooves 130 does not exceed the end portion 139 of the external grooves 136 of the second series of grooves 135.

[0140] Alternatively, any other arrangement could be provided for the external grooves 136 of the second series 135 and the internal grooves 131 of the first series 130.

[0141] The flanges 120 as described make it possible to absorb the expansion of the ferrule 140 at the connection with said ferrule 140 and of the disc itself at the connection with the fixing hub 110 and to maintain a mechanical stress lower than 30% of the elastic limit (or the plasticity threshold) when the flanges are made of thermoplastic materials.

[0142] Generally, the fixing hub 110, the ferrule 140, and the flanges 120 are made of a material compatible with ultra-high vacuum.

[0143] For example, the fixing hub 110, the ferrule 140, and the flanges 120 are made of a metallic material included in the group comprising aluminum, copper, stainless steel or titanium or, in an ultra-high vacuum compatible thermoplastic material included in the group comprising polyetheretherketone (PEEK), polyetherimide (PEI) or polyimide (PI).

[0144] For example, aluminum is 5086, A6061-T6 or A6063-T6 aluminum.

[0145] For example stainless steel is AISI 304L, 304LN, 316L, 321, 347.

[0146] Preferably, the fixing hub 110 is made of a material different from the material of the ferrule 140 and the flanges 120. For example, the fixing hub 110 is made of a low-expansion material to have more constant tightening of the nuts, preferably titanium. The flanges 120 and the ferrule 140 are preferably made of aluminum.

[0147] As illustrated in Figure 1, the airless tire 1 comprises, radially from the inside to the outside, a supporting structure 2, intended to cooperate with the rim 100, a shear band 3 secured to the supporting structure 2 and a tread 4 secured to the shear band 3.

[0148] The supporting structure 2 is constituted, here, of a plurality of spokes 21 regularly distributed circumferentially.

[0149] In a non-limiting manner, the spokes 21 each here comprise an internal end 21 a secured to the rim 100, for example by fixing means (not shown), such as screw means (screws / nuts) or by rivet (not shown), a concave portion 21 b and an external end 21 c secured to the shear band 3 by screw means or by rivet (not shown).

[0150] Said fixing means are configured to fix both a spoke 21 of the tire 1 and the rim 100 at the level of the radial holes 127 made on the flanges 120 and the radial holes 146 made on the ferrule 140.

[0151] The pitch of the external grooves 136 may be dependent or independent of the number of spokes 21 of the tire 1. The fixing means make it possible to fix both a spoke 21 and an external blade 137 of the flanges 120 of the rim 100.

[0152] The shear band 3 comprises, radially from the inside to the outside, a radially inner membrane 31, secured to the outer end 21c of the supporting structure 2, a shear structure 32 and a radially outer membrane 33.

[0153] As illustrated, the shear structure 32 is constituted by a plurality of shear elements 32a, here regularly distributed circumferentially between the radially inner membrane 31 and the radially outer membrane 33.

[0154] In a non-limiting manner, each shear element 32a comprises two opposite curvatures. The supporting structure 2 and the shear strip 3 are each made of a thermoplastic polymer material, said to be high-performance.

[0155] For example, the material constituting at least the supporting structure 2 and the shear band 3 has the following mechanical characteristics, measured according to the ASTM D638 standard of ASTM (American Society for Testing and Materials) International: - Young's modulus in tension E, measured at a temperature equal to 20°C, at least equal to 1 GPa and at most equal to 6 GPa, and, measured at a temperature equal to - 196°C, at least equal to 1.2 GPa and at most equal to 9 GPa, and

[0156] - a maximum tensile stress Sm, measured at a temperature equal to 20°C, at least equal to 25 MPa and at most equal to 150 MPa, and, measured at a temperature equal to - 196°C, at least equal to 40 MPa and at most equal to 260 MPa.

[0157] Thanks to the particular structure of the discs, the rim is subjected to a mechanical stress lower than 30% of the elastic limit (or plasticity threshold) for thermoplastic materials.

Claims

vehicle having an axis of rotation (Xl-Xl) and comprising, as elements of revolution around said axis of rotation (Xl-Xl), and radially from the inside to the outside, a fixing hub (110) intended to be fixed on the vehicle, two flanges (120) each fixed to the fixing hub (110) and a ferrule (140) fixed to each of the flanges (120), characterized in that each flange (120) comprises a truncated cone-shaped body (121), generally in the shape of a hollow truncated cone, extending axially inside the ferrule (140) and delimited axially by a small diameter end (122) connected to the fixing hub (110), and a large diameter end (123) located on the side opposite the fixing hub (110) and connected to a lateral end (144, 145) of the ferrule (140),and in that the frustoconical body (121) of each flange (120) comprises at least a first series (130) of internal grooves (131) extending axially from the small diameter end (122) towards the large diameter end (123) over a length (Lui) at least equal to 10% of the length (Lui) of the generatrix of the frustoconical body (121)., 2. Rim (100) according to claim 1, in which the first series (130) of internal grooves (131) extends axially over a length (Lui) at most equal to 90%, preferably at most equal to 40% of the length (Lui) of the generatrix of the frustoconical body (121).

3. Rim (100) according to claim 1 or 2, in which the first series (130) of internal grooves (131) comprises a plurality of internal grooves (131) circumferentially spaced from each other, two adjacent internal grooves (131) delimiting an internal blade (128), each internal blade (128) comprising at least one axial bore (126) allowing the flange (120) to be fixed to the fixing hub (110).

4. Rim (100) according to any one of the preceding claims, wherein each internal groove (131) of the first series (130) of grooves comprises a main part (132) having a substantially constant width (W132) at least equal to 1 mm and at most equal to 5 mm, preferably at most equal to 1.5 mm, and an end part (133) having a width (W133) greater than the width (W132) of the main part (132).

5. Rim (100) according to claim 4, wherein the main portion (132) of each internal groove (131) extends from the small diameter end (122) over at least 70% to at most 90% of its length (L131).

6. Rim (100) according to claim 4 or 5, wherein the shape of the end portion (133) is non-angular, such as, for example, a drop of water, an oval, an ellipse.

7. Rim (100) according to any one of the preceding claims, in which the frustoconical body (121) of each flange (120) comprises a second series (135) of external grooves (136) extending axially from the large diameter end (123) towards the small diameter end (122) over a length (Li3ô) at least equal to 10% of the length (L121) of the generatrix of the frustoconical body (121).

8. Rim (100) according to claim 7, in which the second series (135) of external grooves (136) extends axially over a length (Li3ô) at most equal to 90%, preferably at most equal to 40% of the length (L121) of the generatrix of the frustoconical body (121).

9. Rim (100) according to claim 7 or 8, in which the second series (135) of external grooves (136) comprises a plurality of external grooves (136) circumferentially spaced from each other, two adjacent external grooves (136) delimiting an external blade (137), each external blade (137) comprising at least one radial bore (127) for fixing the flange (120) to the ferrule (140).

10. Rim (100) according to claim 9, wherein the external grooves (136) of the second series (135) of grooves are arranged in a staggered manner relative to the internal grooves (131) of the first series (130) of grooves.

11. Rim (100) according to claim 9 or 10, wherein the external grooves (136) of the second series (135) of grooves are spaced by a non-zero axial distance relative to the internal grooves (131) of the first series (130) of grooves.

12. Rim (100) according to any one of claims 9 to 11, wherein each external groove (136) comprises a main portion (138) having a substantially constant width (Wi3s) at least equal to 1 mm and at most equal to 5 mm, and an end portion (139) having a width (W139) greater than the width (Wi3s) of the main portion (138), the main portion (138) of each external groove (136) extending from the large diameter end (123) over at least 70% to at most 90% of its length (Li3ô).

13. Rim (100) according to claim 12, wherein the shape of the end portion (139) of each external groove (136) is non-angular, such as, for example, a drop of water, an oval, an ellipse.

14. Rim (100) according to any one of the preceding claims, wherein each flange (120) further comprises a plurality of radial fixing tabs (124) extending radially from the small diameter end (122) towards the axis of rotation (XI-XI) for fixing the flange (120) on the fixing hub (110) and a plurality of axial fixing tabs (125) extending from the large diameter end (123) axially outwards, on the side opposite the small diameter end (122) for fixing the flange (120) on the ferrule (140).

15. Rim (100) according to claims 3 and 14, in which each radial fixing tab (124) comprises at least one axial drilling (126) intended to cooperate with a corresponding axial drilling (112) made on the fixing hub (110) for fixing the flange (120) with fixing means.

16. Rim (100) according to claim 9 in combination with claim 14 or 15, wherein each axial fixing tab (125) comprises the at least one radial drilling (127) intended to cooperate with a corresponding radial hole (146) made on the ferrule (140) for fixing the flange (120) with fixing means.

17. Rim (100) according to any one of the preceding claims, in which the frustoconical body (121) of each flange (120) comprises a thickness (ei2o) at least equal to 0.5 mm and at most equal to 5 mm, for example equal to 0.75 mm.

18. Rim (100) according to any one of the preceding claims, in which the fixing hub (110) comprises an annular base (111) comprising a plurality of axial holes (112) intended to cooperate with fixing means for fixing on the flanges (120).

19. Rim (100) according to claim 18, wherein the fixing hub (110) further comprises a plurality of fixing lugs (113) extending radially from the base (111) towards the axis of rotation (Xl-Xl) of the rim (100), each fixing lug (113) comprising at least one axial bore (114) intended to cooperate with centering means for fixing to the vehicle.

20. Rim (100) according to claim 18 or 19, in which the fixing hub (110) has a thickness (eno) at least equal to 1 mm and at most equal to 10 mm.

21. Rim (100) according to claim 16 in combination with any one of the preceding claims, in which the ferrule (140) comprises a body (141) of generally hollow cylindrical shape comprising a thickness (ei4o) at least equal to 0.5 mm and at most equal to 5 mm, preferably equal to 0.75 mm, the ferrule (140) comprising a plurality of radial holes (140) made at each lateral end of the ferrule (140) and each intended to cooperate with a radial bore (127) made in the flange (120) and fixing means for fixing to the flanges (120).

22. Rim (100) according to any one of the preceding claims, in which the fixing hub (110), the ferrule (140), and the flanges (120) are made of a metallic material included in the group comprising aluminum, copper, stainless steel or titanium or, in a thermoplastic material ultra-high vacuum compatible included in the group consisting of polyetheretherketone (PEEK), polyetherimide (PEI) or polyimide (PI).

23. Mounted assembly (10) or wheel comprising a rim (100) according to any one of the preceding claims and an airless tire (1) mounted on said rim (100).

24. Mounted assembly (10) according to claim 23, wherein the airless tire (1) comprises, radially from the inside to the outside, a supporting structure (2), intended to cooperate with the rim (100), a shear band (3) and a tread (4), the supporting structure (2) comprising a plurality of circumferentially regularly distributed spokes (21) fixed to the rim (100) by fixing means, said fixing means being configured to fix both a spoke (21) of the tire (1) and the rim (100) at the radial holes (127) made on the flanges (120) and radial holes (146) made on the ferrule (140).

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