Rim for bicycle wheel and associated bicycle wheel

Abstract

The invention relates to a rim (10) for a bicycle wheel and an associated bicycle wheel comprising such a rim. The rim (10) comprises an upper bridge (11) configured to allow mounting of a tire, a lower bridge (12) comprising a plurality of perforated spoke attachment seats (12a), and two opposing side walls (20a, 20b) connecting the upper bridge (11) to the lower bridge (12). At least one of the two side walls (20a, 20b) comprises at least one recess (22) having an axial depth that increases as it moves in the recess (22) in a radial direction from the upper bridge (11) towards the lower bridge (12).

Description

Technical Field

[0001] The present invention relates to a rim of a bicycle wheel.

[0002] The present invention also relates to a bicycle wheel comprising the above-mentioned rim. Background Art

[0003] The rim of a bicycle wheel generally comprises an upper bridge configured to allow mounting of a tire (usually by providing suitable fins), a lower bridge comprising a plurality of perforated spoke attachment seats, and two opposing side walls connecting the upper and lower bridges.

[0004] In the present description and claims, the term "perforated spoke attachment seat" is used in the broadest sense to include both perforated seats into which a spoke is directly inserted and perforated seats into which a nipple or other element is inserted, wherein the spoke is for example provided with an enlarged head or has threads, and the nipple or other element is constructed to allow the spoke to be attached to the rim.

[0005] Typically, in cross section of the rim, the portion of the rim defined by the two side walls and by the lower bridge is substantially U-shaped. Summary of the invention

[0006] In the present description and claims, the following definitions apply.

[0007] The term "cross-section" is used to indicate a section taken on a plane intersecting the rim and containing the axis of rotation of the rim.

[0008] The term "radial" is used to refer to the direction perpendicular to the axis of rotation of the rim and intersecting the lower bridge of the rim.

[0009] The term "circumferential" is used to refer to the direction of the annular extension of the rim.

[0010] The term "axial" is used to refer to a direction generally parallel to the axis of rotation of the rim.

[0011] The terms "inner" and "outer" refer to any radial direction of the rim and indicate a position close to the axis of rotation of the rim and a position far from the axis of rotation of the rim, respectively.

[0012] The term "radial extension" is used to indicate the distance between the upper bridge and the lower bridge, such distance being measured in the cross section of the rim.

[0013] Typically, conventional rims have substantially the same radial extension in the circumferential direction. In other words, the radial extension measured in one cross section of a conventional rim is the same as the radial extension measured in any other cross section of the same rim.

[0014] The Applicant has observed that, in order to improve the aerodynamic behavior of conventional rims, rims having a variable radial extension in the circumferential direction have been proposed. Examples of such rims are described in US9610800B2 and US10611188B2. Such rims have a lower bridge which, when viewed transversely, i.e. in the axial direction, has a non-circular extension due to the provision of a plurality of projections projecting radially towards the center of the rim.

[0015] The Applicant has also observed that, also in order to improve the aerodynamic behavior of conventional rims, rims have been proposed whose sidewalls comprise a plurality of surface elements (protrusions or recesses) in order to reduce the aerodynamic drag on the rim itself. An example of such a rim is described in US20140265538A1.

[0016] The applicant has thought about how to improve the aerodynamic behavior of conventional rims and has found a solution that is at least partially different from the solutions suggested in US9610800B2, US10611188B2 and US20140265538A1.

[0017] The technical problem at the basis of the present invention is therefore to provide a rim for a bicycle wheel which has an aerodynamic behavior that is better than the aerodynamic behavior of conventional rims.

[0018] The present invention, in its first aspect, relates to a rim of a bicycle wheel, comprising:

[0019] - an upper bridge configured to allow the mounting of tires;

[0020] - a lower bridge comprising a plurality of perforated spoke attachment seats;

[0021] - two opposing side walls connecting the upper bridge to the lower bridge;

[0022] Characterized in that at least one of the two side walls comprises at least one recess having an axial depth which increases in the recess moving in the radial direction from the upper bridge towards the lower bridge.

[0023] In the present specification and claims, the term "axial depth" of a recess is used to indicate the distance in the axial direction between a point determined on the surface of the recess and a surface including the sidewall of the recess.

[0024] The term "recess" is used to designate a portion of a side wall having an axial depth greater than the axial depth at two portions of the same side wall immediately preceding and immediately following the recess in the circumferential direction. As a result, at all points of the side wall belonging to the recess, the axial distance between the two side walls of the rim is smaller than at all points of the side wall not belonging to the recess.

[0025] The Applicant has found that providing at least one recess as described above on at least one side wall of the rim provides the rim with low aerodynamic resistance to airflow from an axial direction (side wind) and from a direction parallel to the direction of travel of the bicycle (front wind).

[0026] The rim of the present invention may include at least one of the preferred features described below, either alone or in combination.

[0027] Applicants believe that each of these features contributes to improving the aerodynamic behavior of the rim, thereby promoting the flow of air over and / or the detachment of air from the sidewalls of the rim.

[0028] Preferably, the axial depth of the at least one recess gradually increases in the radial direction.

[0029] Preferably, the at least one recess has a maximum axial depth at a circumferential center portion thereof.

[0030] Preferably, the axial depth of the recess increases on the side wall moving from its first circumferential end toward the circumferential center in the circumferential direction, and decreases on the side wall moving from the circumferential center toward the second circumferential end opposite to the first circumferential end.

[0031] Preferably, the at least one recess has a circumferential width measured along a periphery located on the side wall, which circumferential width increases in the recess moving in a radial direction from the upper bridge towards the lower bridge.

[0032] Preferably, the at least one recess extends in the radial direction as far as the lower bridge.

[0033] Preferably, the circumferential width has its maximum at the lower bridge, more preferably at the lower bridge.

[0034] In this way, the recess defines a funnel-shaped area on the side wall of the rim, which allows the air conveyed in the recess to leave the side wall at the lower bridge with low aerodynamic resistance.

[0035] Preferably, the at least one recess has an axial depth that varies as one moves in the recess in a radial direction.

[0036] Preferably, the at least one recess has an axial depth that varies as one moves in the recess in a circumferential direction.

[0037] Due to the gradual variation of the axial depth of the recess in radial and / or circumferential direction, the recess defines a valley-shaped three-dimensional area in the sidewall without surface discontinuities, to favor the structural strength of the rim. Possible surface discontinuities are in fact undesirable because they would constitute tension concentration points.

[0038] Preferably, the at least one recess comprises a minimum depth portion corresponding to a portion of the recess having a minimum axial depth.

[0039] Preferably, the at least one recess comprises a maximum depth portion corresponding to a portion of the recess having a maximum axial depth.

[0040] Preferably, the minimum depth portion is closer to the upper bridge than the maximum depth portion.

[0041] In some preferred embodiments, the at least one recess is symmetrical with respect to a radial direction intersecting the minimum depth portion.

[0042] In other preferred embodiments, the at least one recess is asymmetric with respect to a radial direction intersecting the minimum depth portion.

[0043] In a particularly preferred embodiment, the at least one side wall comprises a plurality of recesses. These recesses provide the side wall with an "undulating" shape in the circumferential direction.

[0044] In the following, when referring to the sidewall of the rim, the term "undulating" or "undulating" is used to indicate a shape defined by a series of protrusions protruding relative to a reference plane, such protrusions being separated by corresponding portions that do not protrude relative to said reference plane or by corresponding portions that protrude on the opposite side relative to said reference plane. Each of the above-mentioned protrusions may be defined by a completely curved surface, or by a surface that is only partially curved, or by a plurality of flat surfaces that follow each other to define a generally curved surface.

[0045] More preferably, the recesses are evenly distributed in the circumferential direction on the at least one side wall. In particular, the recesses are equidistantly spaced from each other in the circumferential direction.

[0046] Preferably, each side wall comprises said at least one recess.

[0047] More preferably, each side wall includes a plurality of recesses evenly distributed in the circumferential direction.

[0048] Even more preferably, the recesses of the two side walls are arranged symmetrically on opposite sides relative to the diametrical mid-plane of the rim. In this way, the rim has the same aerodynamic behavior at both side walls, which has benefits not only in terms of aerodynamics, but also in terms of stability and maneuverability for the rider.

[0049] The term "diametral mid-plane" is used to indicate a plane orthogonal to the axis of rotation of the rim and dividing the rim into two substantially equal parts.

[0050] Preferably, the lower bridge comprises a plurality of perforated spoke attachment seats at the portion of the side wall without recesses. This arrangement facilitates the insertion of spokes or nipples or inserts generally used to reinforce the rim-spoke connection area (possibly provided with nipples) into the rim, in particular when the rim is made of composite material, for example a material comprising structural fibers selected from carbon fibers, glass fibers, boron fibers, synthetic fibers, aramid fibers, ceramic fibers and combinations thereof.

[0051] In a first preferred embodiment of the rim of the invention, the lower bridge has a substantially constant distance from the center of the rim in the circumferential direction.

[0052] In this case, the rim has relief only in the axial direction.

[0053] In a second preferred embodiment of the rim of the present invention, the lower bridge comprises:

[0054] - at least one first circumferential portion having a first distance from the center of the rim;

[0055] - at least one second circumferential portion having a second distance from the centre of the rim different from the first distance.

[0056] Preferably, the distance of the at least one second circumferential portion from the center of the rim is greater than the distance of the at least one first circumferential portion from the center of the rim.

[0057] Preferably, the lower bridge includes a plurality of the first circumferential portions and a plurality of the second circumferential portions.

[0058] In this case, the rim has a "double relief", ie relief in the axial direction (due to the provision of the above-mentioned recess) and in the radial direction (due to the provision of the above-mentioned first and second circumferential portions), which has even greater benefits in terms of aerodynamic behavior.

[0059] In the following, when referring to the lower bridge of the rim, the term "undulating" or "undulating" is used to indicate a shape defined by a series of protrusions protruding relative to a reference perimeter, such protrusions being separated by corresponding portions that do not protrude relative to said reference perimeter or that protrude on the opposite side relative to said reference perimeter. Each of the above-mentioned protrusions may be defined by a completely curved surface, or by a surface that is only partially curved, or by a plurality of flat surfaces that follow one another to define a substantially curved surface.

[0060] Preferably, the perforated spoke attachment seat is arranged at the first circumferential portion.

[0061] Preferably, the first circumferential portions and the second circumferential portions alternate with each other.

[0062] Preferably, the first circumferential portion and the second circumferential portion are evenly distributed in the circumferential direction.

[0063] In particular, the first circumferential portion and the second circumferential portion are equidistantly spaced from each other.

[0064] Preferably, at least a part of the first circumferential portion has a substantially constant distance from the center of the rim in the circumferential direction.

[0065] Preferably, at least a part of the second circumferential portion has a substantially constant distance from the center of the rim in the circumferential direction.

[0066] Preferably, the lower bridge comprises a joining portion defined by a curved surface between the at least one first circumferential portion and the at least one second circumferential portion.

[0067] Therefore, the lower bridge has no surface discontinuities to facilitate the structural strength of the rim.

[0068] Preferably, such a curved surface has an S-shaped profile defined by two peripheries contacting each other at an inflection point.

[0069] Preferably, such an inflection point is arranged halfway along the joint.

[0070] Preferably, one of the two peripheries is tangential to the at least one first circumferential portion at a first junction point.

[0071] Preferably, the other of the two peripheries is tangential to the at least one second circumferential portion at a second junction point.

[0072] Preferably, the two peripheries have different diameters.

[0073] In some preferred embodiments, the at least one recess is defined at the at least one first circumferential portion.

[0074] In other preferred embodiments, the at least one recess is defined at the at least one second circumferential portion.

[0075] In a further preferred embodiment, the at least one recess is defined at the engaging portion.

[0076] In a second aspect of the invention, the invention relates to a bicycle wheel comprising a rim according to the first aspect of the invention, a hub and a plurality of spokes connecting the hub to the rim. Such a wheel thus has the advantages described above with reference to the rim of the invention and preferably has the preferred features described.

[0077] Preferably, said spokes are connected to a lower bridge of the rim at said at least one first circumferential portion or at said at least one second circumferential portion.

[0078] More preferably, said spokes are connected to the rim at said at least one first circumferential portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Other features and advantages of the present invention will become more apparent through the description of preferred embodiments thereof with reference to the accompanying drawings, in which:

[0080] - Figure 1 schematically shows a top view of a bicycle wheel comprising a first embodiment of a rim according to the invention;

[0081] - Figure 2 Schematically shows Figure 1 a stereogram of a portion of a rim;

[0082] - Figure 3 Schematically shows the Figure 2 The cross-sectional planes A and B are cut and overlap each other. Figure 1 Two cross sections of the rim;

[0083] - Figure 4 Schematically shows Figure 1 a top view of a portion of a rim;

[0084] - Figure 5 schematically shows a perspective view of a portion of a second embodiment of a rim according to the invention;

[0085] - Figure 6 Schematically shows the Figure 5 The cross-sectional planes C and D are cut and overlap each other. Figure 5 Two cross sections of the rim;

[0086] - Figure 7 schematically shows a perspective view of a portion of a third embodiment of a rim according to the invention;

[0087] - Figure 8 A perspective view of a portion of a fourth embodiment of a rim according to the invention is schematically shown.

[0088] The above drawings are provided for description and illustration purposes only. The dimensions and proportions shown do not correspond to the actual proportions and dimensions of the corresponding parts of the rim and wheel of the present invention. DETAILED DESCRIPTION

[0089] exist Figure 1 , reference numeral 100 indicates a bicycle wheel including a first embodiment of a rim 10 according to the present invention. Figure 1 The tire and hub of wheel 100 are not shown.

[0090] The rim 10 is particularly suitable for tubeless wheels. However, it should be understood that the invention described and claimed herein is also applicable to rims (clamps) of wheels with air chambers and wheels with tubular tires.

[0091] The rim 10 may be made of a metallic material or at least partially of a composite material.

[0092] In the present specification and claims, the term "composite material" is used to indicate a material comprising a plurality of structural fibers incorporated into a polymer material. Typically, the structural fibers are unidirectional or bidirectional fibers.

[0093] The structural fibers are typically selected from carbon fibers, glass fibers, boron fibers, synthetic fibers, aramid fibers, ceramic fibers, and combinations thereof, with carbon fibers being particularly preferred due to their structural strength and brightness.

[0094] The polymer material of the composite material may be thermoplastic or thermosetting. Preferably, such material is a thermosetting resin. Typically, in the case of a composite material comprising a thermosetting polymer material, the rim 10 is obtained by compression molding, whereas in the case of a composite material comprising a thermoplastic polymer material, the rim 10 is obtained by injection molding.

[0095] The rim 10 has a center X defined on an axis corresponding to the rotation axis of the wheel 100 , and is connected to the hub of the wheel 100 through a plurality of spokes 50 .

[0096] exist Figures 1 to 4 In a non-limiting example, the rim 10 has a symmetrical shape relative to the axis of rotation and a diametrical mid-plane of the rim 10. In such an embodiment, the spokes 50 extend in a substantially radial direction with a predetermined camber. However, alternative embodiments are foreseen in which the rim 10 has an asymmetrical shape and / or in which the spokes 50 extend with different cambers in a direction inclined relative to the radial direction.

[0097] The rim 10 includes an upper bridge 11 , a lower bridge 12 , and two opposing side walls 20 a , 20 b connecting the upper bridge 11 to the lower bridge 12 .

[0098] The upper bridge 11 comprises opposing fins 11a, 11b configured to allow the mounting of tyres.

[0099] A plurality of perforated spoke attachment seats 12a, preferably substantially circular, are formed on the lower bridge 12. Each perforated seat 12a is configured to receive the end of a corresponding spoke 50 or a corresponding nipple or configured to allow the spoke 50 to be attached to other elements of the rim 10.

[0100] The perforated seats 12a are arranged in the position required for the arrangement of the spokes of a particular wheel 100, in other words depending on the number of spokes 50, their distribution along the rim 10, their position in the cross section of the rim 10 and the direction occupied by each spoke 50, for example depending on the radial or tangential attachment of the spokes to the hub and / or the camber angle.

[0101] The radial distance of the lower bridge 12 from the center X of the rim 10 varies in the circumferential direction. In particular, the lower bridge 12 includes a plurality of first circumferential portions 13 and second circumferential portions 14 that are alternately and equidistantly spaced from each other.

[0102] The radial distance from the center X to the first circumferential portion 13 is shorter than the radial distance from the center X to the second circumferential portion 14 .

[0103] like Figure 4 As shown, the first circumferential portion 13 and the second circumferential portion 14 have a circumferential center portion which has a substantially constant radial distance from the center X of the rim 10 in the circumferential direction so as to define respective areas 13a, 14a having a constant radius.

[0104] like Figure 2 As shown, the perforated seat 12 a is located in the first circumferential portion 13 , particularly in a region 13 a having a constant radius in a circumferential center portion of the first circumferential portion 13 .

[0105] In an alternative embodiment not shown, the perforated seat 12 a is located in the second circumferential portion 14 , in particular in a region 14 a having a constant radius in a circumferential center portion of the second circumferential portion 14 .

[0106] In a further alternative embodiment not shown, the perforated seats 12a are situated both in the first circumferential portion 13 and in the second circumferential portion 14 , in particular in the regions 13a , 14a of the circumferential portions 13 , 14 having a constant radius.

[0107] exist Figure 2 In the non-limiting example of, each first circumferential portion 13 comprises a single perforated seat 12a at its circumferential center point. However, alternative embodiments can be envisioned in which each circumferential portion 13 comprises more than one perforated seat 12a.

[0108] The lower bridge 12 includes a joining portion 15 preferably defined by a curved surface between each first circumferential portion 13 and each second circumferential portion 14 adjacent thereto.

[0109] like Figure 4 As shown, such a curved surface more preferably has an S-shaped profile defined by two peripheries E and F which contact each other at an inflection point P located approximately halfway along the joint 15 when passing through the joint 15 in the circumferential direction.

[0110] The periphery E is joined to the first circumferential portion 13 at a first joining point M, and the periphery F is joined to the second circumferential portion 14 at a second joining point N. The joining points M and N define the ends of the joining portion 15 .

[0111] In the junction M, the periphery E and the first circumferential portion 13 share the same tangent. Similarly, in the junction N, the periphery F and the second circumferential portion 14 share the same tangent. In other words, the areas between the first circumferential portion 13 and the junction 15 and between the junction 15 and the second circumferential portion 14 have no steps or irregularities.

[0112] In the non-limiting example shown here, the diameter of the perimeter E is greater than the diameter of the perimeter F. For example, the diameter of the perimeter E is equal to 54 mm, while the diameter of the perimeter F is equal to 38 mm.

[0113] At least one of the two side walls 20 a , 20 b of the rim 10 comprises a plurality of recesses 22 , which preferably have the same shape and are preferably equidistantly spaced from one another in the circumferential direction.

[0114] In a preferred embodiment, the two side walls 20a, 20b comprise a plurality of recesses 22 aligned in the axial direction. Preferably, these recesses 22 are arranged symmetrically on opposite sides with respect to the diametrical midplane of the rim 10.

[0115] like Figure 2 As shown, each recess 22 has an axial depth that gradually changes in the recess 22 as one moves in the radial and circumferential directions, thereby defining a valley-shaped three-dimensional region in the respective sidewall 20a, 20b.

[0116] In particular, each recess 22 extends in the radial direction on the corresponding side walls 20a, 20b to the lower bridge 12, and has a circumferential width that gradually increases from a minimum depth portion 23 of the recess 22 toward the lower bridge 12 as moving in the radial direction in the recess 22, where the recess 22 has a minimum circumferential width until reaching a maximum circumferential width at the lower bridge 12.

[0117] Furthermore, each recess 22 has an axial depth that gradually increases as moving in the radial direction from a minimum depth portion 23 of the recess 22 having the minimum axial depth toward the lower bridge 12 until reaching a maximum axial depth at the lower bridge 12 .

[0118] More specifically, if Figure 2 As shown, each recess 22 is symmetrical with respect to the radial direction R intersecting the minimum depth portion 23 of the recess 22 itself, and the axial depth of the recess 22 increases as it moves from its first circumferential end 22a toward the circumferential center 22c of the recess 22 in the circumferential direction in the recess 22, and decreases as it moves from the circumferential center 22c toward the second circumferential end 22b opposite to the first circumferential end 22a. Therefore, each recess 22 has the maximum axial depth at its circumferential center 22c (more specifically, at the above-mentioned radial direction R) and at the lower bridge 12.

[0119] like Figure 2 As shown, the recess 22 is defined at the second circumferential portion 14 , but an alternative embodiment, not shown, is foreseeable in which the recess 22 is defined at the first circumferential portion 13 .

[0120] like Figure 2 and Figure 3 As shown, the rim 10 has a maximum cross section at each first circumferential portion 13 (one of these cross sections is at Figure 3 It is shown in solid line in Figure 2 and has a minimum cross section at each second circumferential portion 14 (one of these cross sections is at Figure 3 is shown in dashed lines and is Figure 2 (taken at the cross-sectional plane B).

[0121] In the area with the largest cross section, the axial distance between the side walls 20a and 20b and the radial distance between the upper bridge 11 and the lower bridge 12 are the largest, while in the area with the smallest cross section, the axial distance between the side walls 20a and 20b and the radial distance between the upper bridge 11 and the lower bridge 12 are the smallest.

[0122] Thus, regions of largest cross section alternate in the circumferential direction with regions of smallest cross section.

[0123] therefore, Figures 1 to 4The rim 10 has a shape such that its cross section changes continuously and there is no sharp portion between the area with the largest cross section and the area with the smallest cross section. Therefore, the rim 10 has an undulating shape in the axial direction (due to the alternation of the circumferential portions provided with the recessed portions 22 and the circumferential portions without the recessed portions 22 on the side walls 20a and 20b) and in the radial direction (due to the alternation of the first circumferential portion 13 and the second circumferential portion 14 on the lower bridge 12).

[0124] In the embodiment shown here, the area with the largest cross section is arranged radially outer relative to the first circumferential portion 13, and the area with the smallest cross section is arranged radially outer relative to the second circumferential portion 14. Therefore, the perforated seat 12a is arranged at the area with the largest cross section.

[0125] The recess 22 may extend in the radial direction for the entire radial extension of the side walls 20 a and 20 b of the rim 10 , or only for a portion of such radial extension.

[0126] therefore, Figure 3 The point R shown and at which the recess 22 begins can be arranged at any radial distance from the upper bridge 11 .

[0127] Figure 5 and Figure 6 A second preferred embodiment of a rim 10 according to the invention is shown.

[0128] Figure 5 and Figure 6 The rim 10 and Figures 1 to 4 Similar or functionally equivalent parts of the rim 10 are indicated with the same reference numerals and, for their description, reference is made to what has been described above.

[0129] Figure 5 and Figure 6 The rim 10 and Figures 1 to 4 The rim 10 of 10 differs essentially in that the lower bridge 12 has an approximately constant distance from the center X of the rim 10 in the circumferential direction, so that the radial distance between the upper bridge 11 and the lower bridge 12 is approximately equal in all cross sections of the rim 10 .

[0130] Therefore, due to the alternation of the circumferential portions provided with the recessed portions 22 and the circumferential portions without the recessed portions 22 on the side walls 20a and 20b, Figure 5 and Figure 6 The rim 10 has an undulating shape only in the axial direction.

[0131] like Figure 5 As shown, Figure 5 and Figure 6The lower bridge 12 of the rim 10 includes a plurality of circumferential portions 120a provided with perforated seats 12a and a plurality of circumferential portions 120 without perforated seats 12a alternatingly.

[0132] The recessed portion 22 is provided on the side walls 20 a , 20 b at a radially outer position relative to the circumferential portion 120 .

[0133] Therefore, the rim 10 has a maximum cross section at each circumferential portion 120a (one of these cross sections is at Figure 6 is shown in solid lines and is Figure 5 ), and has a minimum cross section at each circumferential portion 120, and therefore has a minimum cross section at each recess 22 (one of these cross sections is at Figure 6 is shown in dashed lines and is Figure 5 (taken at the cross-sectional plane D).

[0134] In the region of the largest cross section, the axial distance between the side walls 20a and 20b is greatest, whereas in the region of the smallest cross section, the axial distance between the side walls 20a and 20b is smallest.

[0135] like Figure 5 As shown, also in Figure 5 and Figure 6 In the rim 10 of FIG. 1 , each recess 22 is symmetrical with respect to a radial direction R intersecting with a minimum depth portion 23 of the recess 22 itself.

[0136] Figure 7 and Figure 8 Two further alternative embodiments of the rim 10 of the present invention are shown.

[0137] Figure 7 The rim 10 and Figures 1 to 4 The rim 10 of FIG. 1 is different mainly in that each recess 22 is asymmetrical with respect to a radial direction R intersecting a minimum depth portion 23 of the recess 22 itself.

[0138] Figure 7 The rim 10 and Figures 1 to 4 Similar or functionally equivalent parts of the rim 10 are denoted by the same reference numerals and, for their description, reference is made to what has already been described above.

[0139] In particular, Figure 7 The rim 10 also has an undulating shape in the axial direction (due to the alternation of circumferential portions with recesses 22 and circumferential portions without recesses 22 on the side walls 20a and 20b) and in the radial direction (due to the alternation of first circumferential portions 12 and second circumferential portions 13 on the lower bridge 22).

[0140] Similarly, Figure 8The rim 10 and Figure 5 and Figure 6 The rim 10 of FIG. 1 is different mainly in that each recess 22 is asymmetrical with respect to a radial direction R intersecting a minimum depth portion 23 of the recess 22 itself.

[0141] Figure 8 The rim 10 and Figure 5 and Figure 6 Similar or functionally equivalent parts of the rim 10 are indicated with the same reference numerals and, for their description, reference is made to what has been described above.

[0142] In particular, due to the alternation of the circumferential portions provided with the recessed portions 22 and the circumferential portions without the recessed portions 22 on the side walls 20a and 20b, Figure 8 The rim 10 has an undulating shape only in the axial direction.

[0143] Obviously, a person skilled in the art may make numerous modifications and variations of the invention in order to meet specific and situational needs, all of which are within the scope of protection defined by the claims.

Claims

1. A rim (10) of a bicycle wheel (100), comprising: - an upper bridge (11) configured to allow the mounting of a tire; - a lower bridge (12) comprising a plurality of perforated spoke attachment seats (12a); - two opposing side walls (20a, 20b) connecting the upper bridge (11) to the lower bridge (12); The invention is characterized in that at least one of the two side walls (20a, 20b) comprises at least one recess (22), and the at least one recess (22) has an axial depth, and the axial depth increases as moving in the recess (22) along the radial direction from the upper bridge (11) toward the lower bridge (12).

2. The rim (10) according to claim 1, wherein: The at least one recess (22) is symmetrical or asymmetrical with respect to a radial direction intersecting a minimum depth portion (23) of the recess (22).

3. The rim (10) according to claim 1, wherein: The at least one recess (22) has a maximum axial depth at a circumferential center portion (22c) thereof.

4. The rim (10) according to claim 1, wherein: The at least one recess (22) has a circumferential width measured along a periphery located on the side wall, the circumferential width increasing as moving in the recess (22) along the radial direction from the upper bridge (11) toward the lower bridge (12).

5. The rim (10) according to claim 3, wherein: The at least one recess (22) extends in the radial direction as far as the lower bridge (12), and wherein the circumferential width is greatest at the lower bridge (12), optionally at the lower bridge (12).

6. The rim (10) according to claim 1, wherein: The at least one recess (22) has an axial depth that gradually changes as one moves in the recess (22) along the radial direction and in the circumferential direction, thereby defining a valley-shaped three-dimensional region in the sidewalls (20a, 20b).

7. The rim (10) according to claim 1, wherein: The at least one side wall (20a, 20b) includes a plurality of recesses (22).

8. The rim (10) according to claim 7, wherein: The recesses (22) are evenly distributed in the circumferential direction on the at least one side wall (20a, 20b).

9. The rim (10) according to claim 1, wherein: The lower bridge (12) has a constant distance from the center (X) of the rim (10) in the circumferential direction.

10. The rim (10) according to claim 1, wherein: The lower bridge (12) comprises: - at least one first circumferential portion (13) having a first distance from the centre (X) of the rim (10); - at least one second circumferential portion (14) having a second distance from the centre (X) of the rim (10), said second distance being different from said first distance.

11. The rim (10) according to claim 10, wherein: The lower bridge (12) includes a plurality of the first circumferential portions (13) and a plurality of the second circumferential portions (14).

12. The rim (10) according to claim 11, wherein: The first circumferential portions (13) and the second circumferential portions (14) alternate with each other in a circumferential direction and are evenly distributed.

13. The rim (10) according to claim 10, wherein the lower bridge (12) comprises a joining portion (15) defined by a curved surface between the at least one first circumferential portion (13) and the at least one second circumferential portion (14).

14. The rim (10) according to claim 13, wherein: The curved surface has an S-shaped profile defined by two peripheries (E, F) contacting each other at an inflection point (P), and wherein one periphery (E) of the two peripheries (E, F) is tangent to the at least one first circumferential portion (13) at a first joining point (M), and the other periphery (F) of the two peripheries (E, F) is tangent to the at least one second circumferential portion (14) at a second joining point (N).

15. The rim (10) according to claim 14, wherein: The inflection point (P) is located halfway along the joint (15).

16. The rim (10) according to claim 10, wherein: The at least one recessed portion (22) is defined at one of the at least one first circumferential portion (13), the at least one second circumferential portion (14), and the engaging portion (15).

17. A bicycle wheel (100), comprising: The rim (10) according to claim 1; hub; and a plurality of spokes (50) connecting the hub to the rim (10).

18. The bicycle wheel (100) according to claim 17, comprising the rim (10) according to claim 10, wherein The spokes (50) are connected to the lower bridge (12) of the rim (10) at the at least one first circumferential portion (13) or at the at least one second circumferential portion (14).

Images