Wheel rim for an extraterrestrial vehicle and wheel.
The wheel rim design with grooved flanges and materials like aluminum addresses the issue of thermal stress in extraterrestrial vehicles, ensuring structural integrity and lightweight performance across extreme temperatures.
Patent Information
- Application Number
- FR2023013793
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-12-07
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2043-12-07
AI Technical Summary
Rigid metal rims used in extraterrestrial vehicles cannot withstand extreme temperature variations, leading to high stresses due to differential thermal expansion, exceeding the elastic limit and causing structural unsustainability.
A wheel rim design featuring flanges with internal and external grooves that allow for thermal expansion, maintaining mechanical stress below 30% of the elastic limit, using materials like aluminum, copper, stainless steel, or titanium, and incorporating an airless tire with a load-bearing structure.
The rim design effectively absorbs thermal expansion effects, reducing stress concentrations and maintaining structural integrity across extreme temperature gradients, while being lightweight and compatible with extraterrestrial environments.
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Abstract
Description
Title of the invention: Wheel rim for an extraterrestrial vehicle and wheel. Technical field of the invention
[0001] The present invention relates to the field of a wheel rim intended to equip an extraterrestrial exploration vehicle, designed 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. Prior art
[0002] Metal rims have been made to equip extraterrestrial vehicles.
[0003] However, known rigid metal rims cannot withstand a thermal gradient in the aforementioned temperature range.
[0004] Indeed, when using known rigid metal rims in an environment subject to very high temperature variations, the different parts of the wheel can undergo differentiated thermal expansion, which generates high stresses, particularly at the connection between these different parts. Stresses exceeding the elastic limit are observed in some of the parts constituting the rim, which is not structurally sustainable.
[0005] Thus, there is a need to remedy the aforementioned drawbacks. Description of the invention
[0006] The inventors aim to design a rim for a wheel that is both rigid and capable of withstanding conditions in an extraterrestrial environment, in a temperature range from very low to very high temperatures, typically within the range [-243°C; +130°C], while also being lightweight.
[0007] The present invention relates to a wheel rim for 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 out, a fixing hub intended to be fixed on the vehicle, two discs or flanges each fixed to the fixing hub and a ferrule fixed to each of the flanges.
[0008] In other words, said ferrule radially surrounds the fixing hub and the flanges.
[0009] Each flange comprises a frustoconical body, generally in the shape of a hollow frustocone, extending axially inside the ferrule and axially delimited by a small-diameter end connected to the fixing hub and a large-diameter end diameter located on the opposite side of the fixing hub, and connected to the lateral ends of the ferrule.
[0010] The frustoconical body of each flange comprises at least a first series of internal grooves extending axially from the end of small diameter to the end of large diameter over a length at least equal to 10% of the total length of the generatrix of the frustoconical body.
[0011] For example, the first series of internal grooves extends axially from the small-diameter end to the large-diameter end over a length preferably not exceeding 90%, and preferably not exceeding 40%, of the total length of the generatrix of the frustoconical body. Such a rim makes it possible to reduce the stresses related to the thermomechanical cycles of the rim during temperature variations.
[0012] The internal grooves made in the frustoconical body of each flange allow the expansion of the ferrule at the point of the connection between the flange and said ferrule and the expansion of the flange itself at the point of its connection with the fixing hub and to maintain a mechanical stress less than 30% of the elastic limit (or the plasticity threshold) when the flanges are made of thermoplastic materials.
[0013] Furthermore, the length of the internal grooves allows for good flexibility in the fixing hub.
[0014] Advantageously the two flanges are identical to each other.
[0015] Advantageously, the first series of internal grooves comprises a plurality of circumferentially, preferably regularly spaced internal grooves, with two adjacent internal grooves delimiting an internal blade, each internal blade comprising at least one axial hole allowing the flange to be fixed to the fixing hub.
[0016] Preferably, the internal grooves are formed in the thickness of each flange. Consequently, they open onto the internal and external surfaces of the frustoconical body.
[0017] 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 flared in shape, having a width greater than the width of the main part.
[0018] The wider end portion of each internal groove, compared to the main portion, helps to limit localized stress concentrations. The width of the internal grooves allows the torsional stiffness of the flange to be modified by changing the width of the remaining material, that is to say the internal blades.
[0019] Preferably, the main part of each internal groove extends from the small diameter end for at least 70% to at most 90% of its length.
[0020] For example, the shape of the end part is non-angular, such as, for example, a teardrop, an oval, an ellipse.
[0021] According to one embodiment, the frustoconical body of each flange comprises a second series of external grooves extending axially from the end of large diameter to the end of small diameter over a length at least equal to 10% of the length of the generatrix of the frustoconical body.
[0022] 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.
[0023] The combination of the first series of internal grooves and the second series of external grooves makes it possible to absorb the effects of thermal expansion.
[0024] Furthermore, the second series of external grooves makes it easier to produce the flanges by cone-forming the discs through mechanical deformation.
[0025] Advantageously, the second series of external grooves comprises a plurality of circumferentially, preferably regularly spaced external grooves, with two adjacent external grooves delimiting an external blade, each external blade comprising at least one radial hole for fixing the flange to the ferrule.
[0026] For example, the external grooves are made in the thickness of each disc. Consequently, they open onto the internal and external surfaces of the frustoconical body.
[0027] According to a non-limiting embodiment, the external grooves of the second series of grooves are arranged in a staggered pattern with respect to the internal grooves of the first series of grooves.
[0028] This makes it possible to obtain 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 frustoconical body is obtained.
[0029] Preferably, the external grooves of the second series of grooves are spaced at a non-zero axial distance from the internal grooves of the first series of grooves.
[0030] Without limiting the limit, the end part of the internal grooves of the first series of grooves does not exceed the end part of the external grooves of the second series of grooves.
[0031] Alternatively, the external grooves of the second series of grooves could be 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.
[0032] Alternatively, any other arrangement could be provided for the external grooves of the second series and the internal grooves of the first series.
[0033] Advantageously, each external groove comprises a main part having a width, that is to say the dimension considered in the circumferential direction, substantially constant of at least 1 mm and at most 5 mm, preferably at most 1.5 mm, and an end part, for example flared in shape, having a width greater than the width of the main part, the main part of each external groove extending from the end of large diameter for at least 70% to at most 90% of its length.
[0034] The end portion, which is wider than the main portion of each external groove, helps to limit localized stress concentrations.
[0035] For example, the shape of the end part of each external groove is non-angular, such as, for example, a teardrop, an oval, an ellipse.
[0036] 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.
[0037] For example, each flange includes a number of internal grooves between thirty and seventy-two.
[0038] For example, each flange includes a number of external grooves between thirty and seventy-two.
[0039] 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 on the fixing hub and a plurality of axial fixing tabs extending from the large diameter end axially outwards, on the opposite side to the small diameter end for fixing the flange on the ferrule.
[0040] In other words, the flanges are assembled together via the fixing hub.
[0041] For example, each radial fixing tab includes at least one axial hole intended to cooperate with a corresponding axial hole made on the fixing hub for fixing the flange with fixing means.
[0042] The number of axial holes is preferably equal to the number of axial holes in the fixing hub.
[0043] For example, each axial fixing tab includes at least one radial drilling intended to cooperate with a corresponding radial hole made on the ferrule for fixing the flange with fixing means.
[0044] The number of radial holes is preferably equal to the number of radial holes in the ferrule.
[0045] For example, the small diameter end of the frustoconical body of each flange preferably has an external diameter of 230 mm.
[0046] For example, the large diameter end of the frustoconical body of each flange preferably has an external diameter of 397 mm.
[0047] For example, the frustoconical body of each flange includes a thickness, that is to say the dimension considered in a direction perpendicular to the direction of extension of the frustoconical body, of at least 0.5 mm and at most 5 mm, for example equal to 0.75 mm.
[0048] For example, the frustoconical body of each flange comprises a total length, that is to say the dimension considered in the direction of extension of the frustocone for example equal to 147.5 mm.
[0049] According to one embodiment, the fixing hub comprises an annular base, preferably substantially flat, comprising a plurality of axial holes intended to cooperate with fixing means, for example screws / nuts or rivets, for fixing to the flanges.
[0050] Advantageously, the mounting hub further comprises a plurality of mounting lugs extending radially from the base towards the axis of rotation of the rim, each mounting lug comprising at least one axial bore intended to cooperate with centering means, for example screws / nuts or rivets, for fixing to the vehicle.
[0051] For example, the fixing lugs are circumferentially regularly distributed on the radially inner surface of the base of the fixing hub.
[0052] For example, and in no way limiting the application, the mounting hub comprises six mounting tabs. Generally, the mounting hub comprises at least two mounting tabs for attachment to the extraterrestrial vehicle.
[0053] For example, the mounting hub has a thickness, that is to say the dimension taken along the axial direction, of at least 1 mm and at most 10 mm. This makes it possible to limit the mass of the mounting hub.
[0054] 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.
[0055] According to one embodiment, the ferrule comprises a generally cylindrical hollow body having a thickness, that is to say the dimension taken along the radial direction, of at least 0.5 mm and at most 5 mm, preferably 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 bore made in the flange and means for fixing, for example screws / nuts or rivets, for fixing to the flanges.
[0056] The body of the ferrule is, for example, radially delimited by an internal surface and an external surface and axially by two opposing lateral surfaces.
[0057] The outer diameter and axial distance of the ferrule depend on the dimensions of the tire. For example, the outer diameter of the ferrule is 398.5 mm for an axial distance of 300 mm.
[0058] 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.
[0059] Without limiting the information, the rim is symmetrical with respect to a plane passing through the axis rotation and with respect to a median plane to the ferrule perpendicular to the axis of rotation.
[0060] The two frustoconical bodies may or may not be identical.
[0061] One could also foresee a geometry of the grooves 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 aluminium, copper, stainless steel or titanium or of an ultra-high vacuum compatible thermoplastic material included in the group comprising polyetheretherketone (PEEK), polyetherimide (PEI) or polyimide (PI).
[0063] For example, the aluminum is an aluminum 5086, A6061-T6 or A6063-T6.
[0064] For example, stainless steel is AISI 304L, 304LN, 316L, 321, 347 steel.
[0065] Preferably, the fixing hub is made of a different material than the material of the ferrule and flanges. For example, the fixing hub is made of a low-expansion material to ensure more consistent tightening of the nuts, preferably titanium.
[0066] The flanges and the ferrule are preferably made of aluminium.
[0067] According to another aspect, the invention relates to an 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 out, a load-bearing structure, intended to cooperate with the rim, a shear strip and a tread, the load-bearing structure comprising a plurality of circumferentially regularly distributed spokes fixed to the rim by fastening means, said fastening means being configured to fix both a spoke of the tire and the rim at the radial holes made on the flanges and radial holes made on the ferrule.
[0069] The pitch of the external grooves may be dependent or independent of the number of spokes of the tire. The fastening means allow for the fixing of a spoke at a time. and an outer blade of the rim flanges.
[0070] For example, at least the load-bearing structure and the shear strip are each made of at least one material having the following mechanical characteristics, measured according to ASTM D638 (American Society for Testing and Materials International): - Young's modulus in tension E, measured at a temperature of 20°C, is at least 1 GPa and at most 6 GPa, and, measured at a temperature of -196°C, is at least 1.2 GPa and at most 9 GPa, and -a maximum tensile stress Sm, measured at a temperature of 20°C, of at least 25 MPa and at most 150 MPa, and, measured at a temperature of -196°C, of at least 40 MPa and at most 260 MPa. Brief description of the drawings
[0071] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:
[0072] [Fig.1] represents an overall perspective view of an assembled wheel comprising a rim according to an embodiment of the invention and an airless tire;
[0073] [Fig.2] illustrates in perspective the rim according to [Fig.l];
[0074] [Fig.2A] is an exploded view of [Fig.2];
[0075] [Fig.3] is a side view of the rim of [Fig.2];
[0076] [Fig.4] is a cross-sectional view of the rim according to the section plane IV-IV of [Fig.3];
[0077] [Fig.5] illustrates a disc from the rim of [Fig.2]; and
[0078] [Fig.5A] is a detail of [Fig.5].
[0079] Detailed description of at least one embodiment
[0080] In the following description, the terms "circumferential", "axial" and "radial" are defined with respect to the Xl-Xl axis of rotation of the rim 100.
[0081] The "circumferential" direction designates a direction in a plane perpendicular to the axis of rotation Xl-Xl of the rim 100 and tangent to the tread, the "Axial" direction is the direction of the Xl-Xl rotation axis of the 100 rim and a "radial" direction refers to a direction perpendicular to the Xl-Xl rotation axis of the 100 rim.
[0082] The [Fig.1] is an overall perspective view of an assembled wheel 10 comprising a rim 100 and a tire 1 mounted on said rim 100.
[0083] The rim 100 is intended to equip a wheel of an extraterrestrial vehicle and is capable to withstand strong temperature gradients ranging from -243°C to +130°C.
[0084] By "rim" we mean a structure for connection with the vehicle and central support of the tire 1.
[0085] The rim 100 comprises, as elements of revolution about said axis of rotation XL-XL, and radially from the inside out, 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.
[0086] The fixing hub 110 forms the fixing interface between the wheel 10 and the vehicle.
[0087] The mounting hub 110 includes an annular base 111, here substantially plane, comprising a plurality of axial holes 112 intended to cooperate with fastening means (not shown), for example screws / nuts or rivets, for fastening to the flanges 120.
[0088] The mounting hub 110 further includes a plurality of mounting tabs 113 extending radially from the base 111 towards the axis of rotation Xl-Xl of the rim 100. Each mounting tab 113 includes an axial bore 114 intended to cooperate with centering means (not shown), for example screws / nuts or rivets, for attachment to the extraterrestrial vehicle.
[0089] The fixing tabs 113 are, here, circumferentially regularly distributed on the radially inner surface of the base 111 of the fixing hub 110.
[0090] As illustrated, and in no way limiting, the mounting hub 110 includes six mounting tabs 113. Generally, the hub 110 includes at least two mounting tabs 113 for attachment to the extraterrestrial vehicle.
[0091] The thickness en0 of the fixing hub 110, here the dimension taken along the radial direction, is between 1 mm and 10 mm, in order to limit the mass of the fixing hub 110.
[0092] The outside diameter Dn0 of the fixing hub 110 depends on the dimensions of the flanges 12.
[0093] For example, the outer diameter Dnodu fixing hub 110 is between 235 mm and 260 mm.
[0094] 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.
[0095] The body 141 comprises a thickness ei40, here the dimension taken along the radial direction, between 0.5mm and 5 mm, preferably equal to 0.75 mm.
[0096] The outside diameter and the axial length or distance of the ferrule 140 depend on the dimensions of the tire 1. For example, the outside diameter of the ferrule 140 is equal to 398.5 mm for an axial length of 300 mm.
[0097] Each lateral end of the ferrule 140 includes a plurality of radial holes 146, each intended to cooperate with fastening means (not shown), for example screws / nuts or rivets, for fastening 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] Without limiting the foregoing, the rim 100 is, in this instance, symmetrical with respect to a plane passing through the axis of rotation XI-XI and with respect to a median plane at the ferrule 140 perpendicular to the axis of rotation XI-XL. Alternatively, it could be provided that the rim 100 is not symmetrical with respect to a median plane at the ferrule 140 perpendicular to the axis of rotation XI-XL.
[0100] The 120 flanges are, here, identical to each other.
[0101] Alternatively, it could be envisaged that the flanges 120 are not identical in terms of dimensions.
[0102] Each flange 120 comprises a frustoconical body 121 of general shape in the form of a hollow frustocone extending axially inside the ferrule 140.
[0103] The frustoconical body 121 is axially delimited by a small diameter end 122 and a large diameter end 123.
[0104] The flanges 120 are assembled together via 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 includes 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.
[0107] The radial fixing tabs 124 extend radially inwards from the small diameter end 122, i.e. towards the axis of rotation XI-XL
[0108] Each radial mounting tab 124 includes, here, an axial bore 126 intended to cooperate with a corresponding axial bore 112 made on the annular base 111 of the mounting hub 110 for attachment with fastening means. Alternatively, each radial mounting tab 124 could be provided to include a number of axial holes 126 greater than or equal to two. The number of axial holes 126 is equal to the number of axial holes 112 of the fixing hub 110.
[0109] The axial fixing tabs 125 extend from the large diameter end 123 axially outwards, on the opposite side to the small diameter end 122.
[0110] Each axial fixing tab 125 includes, 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.
[0111] Alternatively, each axial fixing tab 125 could be provided to include two or more radial holes 127. The number of radial holes 127 is equal to the number of radial holes 146 in the ferrule 140.
[0112] By way of non-limiting example, the small diameter end 122 has an external diameter Di22 preferably equal to 230 mm.
[0113] The large diameter end 123 has, for example, an external diameter D[23 preferably equal to 397 mm.
[0114] The thickness of the frustoconical body 121 of each flange 120, that is to say the dimension considered in a direction perpendicular to the direction of extension of the frustocone, is, for example, between 0.5 mm and 5 mm, for example equal to 0.75 mm.
[0115] The total length L[2i 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.
[0116] 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 end of small diameter 122 to the end of large diameter 123 over a length L^at least equal to 10% of the length Lui of the generatrix of the frustoconical body.
[0117] For example, 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 L121 of the generatrix of the frustoconical body (121).
[0118] The length of the internal grooves 131 allows for good flexibility in the fixing hub 110.
[0119] 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.
[0120] Each internal blade 128 includes at least the axial hole 126 for fixing the flange 120 to the fixing hub 110.
[0121] The internal grooves 131 are, here, made in the thickness of each flange. By Consequently, they open onto the internal and external surfaces of the truncated conical body 121.
[0122] Each internal groove 131 comprises a main part 132 having a width W 132, 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 Wi33 greater than the width Wi32 of the main part 132.
[0123] The shape of the end portion 133 of each internal groove 131 here represents a teardrop. 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.
[0124] The end part 133, which is wider than the main part 132 of each internal groove 131, helps to limit localized stress concentrations.
[0125] The main part 132 of each internal groove 131 extends from the small diameter end 122 for at least 70% to at most 90% of its length Li3).
[0126] The width Wi32 Wi33 of the internal grooves 131 allows the stiffness of torsion by changing the width of the remaining material, i.e. the internal 128 disc blades.
[0127] For example, each flange 120 includes a number of internal grooves 131 between 30 and 72.
[0128] As illustrated in the figures, and in no way limitingly, the frustoconical body 121 of each flange 120 comprises a second series 135 of external grooves 136 extending axially from the end of large diameter 123 to the end of small diameter 122 over a length Ln6 at least equal to 10% of the length L121 of the generatrix of the frustoconical body (121).
[0129] For example, the second series 135 of external grooves 136 extends axially over a length Li36 of at most equal to 90%, preferably at most equal to 40% of the length L121 of the generatrix of the frustoconical body 121.
[0130] Alternatively, it could be provided that the frustoconical body 121 of each flange 120 comprises only the first series 130 of internal grooves 131.
[0131] 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.
[0132] Each external blade 137 includes at least one radial hole 127 for fixing the flange 120 to the ferrule 140.
[0133] The external grooves 136 are, here, made in the thickness of each disc. Consequently, they open onto the inner and outer surfaces of the trunk of a cone.
[0134] Each external groove 136 comprises a main part 138 having a width W 138, 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 Wi39 greater than the width Wi38 of the main part 138.
[0135] The shape of the end portion 139 of each external groove 136 represents here a teardrop. 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.
[0136] The end part 139, which is wider than the main part 138 of each external groove 136, helps to limit localized stress concentrations.
[0137] The main part 138 of each external groove 136 extends from the large diameter end 123 over at least 70% to at most 90% of its length Li36.
[0138] The width of the external grooves 136 allows the torsional stiffness to be modified by modifying the width of the remaining material, i.e. the external blades 137.
[0139] For example, each flange 120 includes a number of external grooves 136 between 30 and 72.
[0140] 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.
[0141] Furthermore, the second series of external grooves makes it easier to cone-form the flanges 120 by mechanical deformation.
[0142] As illustrated, and in no way limiting, the external grooves 136 of the second series 135 are arranged in a staggered pattern with respect 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 can be obtained up to 90% of the curvilinear length of the frustoconical body 121.
[0143] The internal grooves 131 of the first series of grooves 130 are, here, spaced at a non-zero axial distance from the external grooves 136 of the second series of grooves 135.
[0144] As illustrated, and in no way limiting, the end part 133 of the internal grooves 131 of the first series of grooves 130 does not exceed the end part 139 of the external grooves 136 of the second series of grooves 135.
[0145] 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.
[0146] The flanges 120 as described allow the expansion of the ferrule 140 to be absorbed at the point of contact with said ferrule 140 and of the disc itself at the point of contact with the 110 fixing hub and to maintain a mechanical stress less than 30% of the elastic limit (or plasticity threshold) when the flanges are made of thermoplastic materials.
[0147] Generally, the fixing hub 110, the ferrule 140, and the flanges 120 are made of a material compatible with ultra-high vacuum.
[0148] For example, the fixing hub 110, the ferrule 140, and the flanges 120 are made of a metallic material included in the group comprising aluminium, 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).
[0149] For example, aluminium is aluminium 5086, A6061-T6 or A6063-T6.
[0150] For example, stainless steel is AISI 304L, 304LN, 316L, 321, 347 steel.
[0151] Preferably, the fixing hub 110 is made of a different material 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 a more constant tightening of the nuts, preferably titanium.
[0152] The flanges 120 and the ferrule 140 are preferably made of aluminium.
[0153] As illustrated in [Fig.1], the airless tire 1 comprises, radially from the inside out, a carrier structure 2, intended to cooperate with the rim 100, a shear strip 3 integral with the carrier structure 2 and a tread 4 integral with the shear strip 3.
[0154] The supporting structure 2 is made up, here, of a plurality of radii 21 regularly distributed circumferentially.
[0155] Without limitation, the spokes 21 each here comprise an inner end 21a attached to the rim 100, for example by means of fastening (not shown), such as screws (screws / nuts) or rivets (not shown), a concave portion 21b and an outer end 21c attached to the shear strip 3 by means of screws or rivets (not shown).
[0156] Said fastening means are configured to fix both a radius 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.
[0157] The pitch of the external grooves 136 can be dependent or independent of the number of spokes 21 of the tire 1. The fastening means allow both a spoke 21 and an external blade 137 of the flanges 120 of the rim 100 to be fixed.
[0158] The shear strip 3 comprises, radially from the inside out, a radially inner membrane 31, integral with the outer end 21c of the supporting structure 2, a shear structure 32 and a radially outer membrane 33.
[0159] As illustrated, the shear structure 32 consists of a plurality of shear elements 32a, here regularly distributed circumferentially between the radially inner membrane 31 and the radially outer membrane 33.
[0160] Without limitation, each shear element 32a comprises two opposing curvatures.
[0161] The load-bearing structure 2 and the shear strip 3 are each made of a high-performance thermoplastic polymeric material.
[0162] For example, the material constituting at least the load-bearing structure 2 and the shear strip 3 have the following mechanical characteristics, measured according to ASTM D638 of the ASTM (American Society for Testing and Materials) International: - Young's modulus in tension E, measured at a temperature of 20°C, is at least 1 GPa and at most 6 GPa, and, measured at a temperature of -196°C, is at least 1.2 GPa and at most 9 GPa, and -a maximum tensile stress Sm, measured at a temperature of 20°C, of at least 25 MPa and at most 150 MPa, and, measured at a temperature of -196°C, of at least 40 MPa and at most 260 MPa.
[0163] Thanks to the particular structure of the discs, the rim is subjected to a mechanical stress less than 30% of the elastic limit (or the plasticity threshold) for thermoplastic materials.
Claims
Demands
1. Rim (100) for a wheel (10) of a vehicle having an axis of rotation (XI-XI) and comprising, as elements of revolution about said axis of rotation (Xl-Xl), and radially from the inside out, a mounting hub (110) intended to be fixed to the vehicle, two flanges (120) each fixed to the mounting hub (110) and a ferrule (140) fixed to each of the flanges (120), characterized in that each flange (120) comprises a frustoconical body (121), generally in the form of a hollow frustocone, extending axially inside the ferrule (140) and axially delimited by a small diameter end (122) connected to the mounting hub (110), and a large diameter end (123) located on the side opposite the mounting 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 end of small diameter (122) to the end of large diameter (123) over a length (Lui) at least equal to 10% of the length (L12i) of the generatrix of the frustoconical body (121).
2. Rim (100) according to claim 1, wherein the first series (130) of internal grooves (131) extends axially over a length (L i3i) at most equal to 90%, preferably at most equal to 40% of the length (L12i) of the generatrix of the frustoconical body (121).
3. Rim (100) according to claim 1 or 2, wherein the first series (130) of internal grooves (131) comprises a plurality of circumferentially spaced internal grooves (131), two adjacent internal grooves (131) delimiting an internal blade (128), each internal blade (128) comprising at least one axial hole (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 (Wi32) of at least 1 mm and at most 5 mm, preferably at most 1.5 mm, and an end part (133) having a width (Wi33) greater than the width (Wi32) of the main part (132).
5. Rim (100) according to claim 4, wherein the main part (132) of each internal groove (131) extends from the end of the small diameter (122) over at least 70% to at most 90% of its length (Lni).
6. Rim (100) according to claim 4 or 5, wherein the shape of the end part (133) is non-angular, such as, for example, a teardrop, an oval, an ellipse.
7. Rim (100) according to any one of the preceding claims, wherein 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) to the small diameter end (122) over a length (Li36) at least equal to 10% of the length (L121) of the generatrix of the frustoconical body (121).
8. Rim (100) according to claim 7, wherein 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).
9. Rim (100) according to claim 7 or 8, wherein 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 hole (127) for the attachment of 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 pattern with respect 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 at a non-zero axial distance from 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 part (138) having a substantially constant width (Wi38) of at least 1 mm and at most 5 mm, and an end part (139) having a width (Wi39) greater than the width (Wi38) of the main part (138), the main part (138) of each external groove (136) extending from the large diameter end (123) for at least 70% to at most 90% of its length (Ln6).
13. Rim (100) according to claim 12, wherein the shape of the end part (139) of each external groove (136) is non-angular, such as, for example, a teardrop, 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 (Xl-Xl) for fixing the flange (120) to the fixing hub (110) and a plurality of axial fixing tabs (125) extending axially outwards from the large diameter end (123) on the opposite side to the small diameter end (122) for fixing the flange (120) to the ferrule (140).
15. Rim (100) according to claims 3 and 14, wherein each radial fixing tab (124) comprises at least one axial hole (126) intended to cooperate with a corresponding axial hole (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 at least one radial bore (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, wherein the frustoconical body (121) of each flange (120) comprises a thickness (ei2o) of at least 0.5 mm and at most 5 mm, for example equal to 0.75 mm.
18. Rim (100) according to any one of the preceding claims, wherein the fixing hub (110) comprises an annular base (111) comprising a plurality of axial holes (112) intended to cooperate with fixing means for fixing to 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) to 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, wherein the hub of fixing (110) has a thickness (en0) of at least 1 mm and at most 10 mm.
21. Rim (100) according to claim 16 in combination with any one of the preceding claims, wherein the ferrule (140) comprises a body (141) of generally hollow cylindrical shape comprising a thickness (ei40) of at least 0.5 mm and at most 5 mm, preferably 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 fastening means for fastening to the flanges (120).
22. Rim (100) according to any one of the preceding claims, wherein the fixing hub (110), the ferrule (140), and the flanges (120) are made of a metallic material included in the group comprising aluminium, copper, stainless steel or titanium or, of an ultra-high vacuum compatible thermoplastic material included in the group comprising polyetheretherketone (PEEK), polyetherimide (PEI) or polyimide (PI).
23. Assembled 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. Assembly (10) according to claim 23, wherein the airless tire (1) comprises, radially from the inside out, a carrier structure (2), intended to cooperate with the rim (100), a shear strip (3) and a tread (4), the carrier structure (2) comprising a plurality of circumferentially regularly distributed spokes (21) fixed to the rim (100) by fastening means, said fastening 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 collar (140).