Bicycle wheel rim and process for manufacturing the same

Abstract

The present invention relates to a bicycle rim comprising a wall (56) made of a composite material having a plurality of perforated spoke attachments (58), wherein at least one of the perforated spoke attachments (58) is defined at least partially by: - ​​at least one first region (62) comprising end portions of a first plurality of cut structural fibers (60a); - at least one second region (63) circumferentially spaced from the at least one first region (62) and comprising end portions of a second plurality of cut structural fibers (60b) and a first portion of a continuous structural fiber (60c), the longitudinal dimension of the second plurality of cut structural fibers (60b) being greater than the longitudinal dimension of the structural fiber of the first plurality of cut structural fibers (60a). At least some of the end portions of the structural fibers of the second plurality of cut structural fibers (60b) are in a state of being parallel or interposed to each other relative to the first portion of the continuous structural fiber (60c). The present invention also relates to a method for manufacturing the aforementioned wheel rim.

Description

Technical Field

[0001] This invention relates to a bicycle rim.

[0002] The present invention also relates to a method for manufacturing the aforementioned wheel rim. Prior Technology

[0003] The rim of the present invention comprises a composite material, at least in the wall in which the perforated spoke attachments are formed. Hereinafter, such a rim will also be identified as a "rim made of composite material".

[0004] In this specification and the accompanying claims, the term "perforated spoke attachment" is used in a broad sense to include both a mount into which a spoke is directly inserted, the spoke having, for example, an enlarged head and / or threads; and a mount into which a connector or other element associated with the spoke is inserted.

[0005] In this specification and the appended claims, the term "composite material" is used to refer to a material comprising a plurality of structural fibers incorporated into a polymeric material. Typically, the aforementioned structural fibers are unidirectional or bidirectional fibers. In a first case, a single layer of unidirectional fibers or at least two side-by-side layers of unidirectional fibers inclined relative to each other may be provided, each layer of structural fibers being arranged such that, in the rim region away from the perforated spoke attachment, they extend substantially parallel to each other along their respective longitudinal directions. In a second case, the composite material defines a fabric comprising a first plurality of substantially parallel structural fibers (weft fibers) extending along the aforementioned first longitudinal direction and a second plurality of substantially parallel structural fibers (warp fibers) extending along a second direction substantially perpendicular to the aforementioned first direction.

[0006] In the following text, when referring to unidirectional fibers, the structural fibers of the unidirectional fiber layer will be mentioned.

[0007] Wheel rims made of composite materials are known. They are typically manufactured by molding composite materials according to various cross-sectional shapes.

[0008] Typically, compression molding is performed when the composite material includes thermosetting polymers, while injection molding or thermoforming is performed when the composite material includes thermoplastic polymers.

[0009] Before the rim and hub are associated to form a bicycle wheel, multiple perforated spoke attachments must be formed in the rim.

[0010] Depending on the number of spokes, the distribution of the perforated seats along the circumference of the rim, the position of the perforated seats in the cross-section of the rim, and the direction occupied by each spoke (e.g., due to the radial or tangential attachment of the spokes to the hub and / or due to the camber), the aforementioned perforated seats must be formed in the positions required for the spoke pattern of a particular wheel.

[0011] The applicant's patent applications EP 2422959 and US 10315461 disclose a method for manufacturing bicycle rims made of composite materials, wherein a plurality of perforated spoke attachments are manufactured before molding the composite material, thereby obtaining a bicycle rim with the aforementioned perforated attachments after molding. Specifically, before molding the composite material, the perforated spoke attachments are formed at desired positions by displacement of structural fibers.

[0012] In EP 2422959, this displacement is achieved by using a non-cutting pointed tool such as an awl. Once inserted into the composite material, this tool causes localized displacement of the structural fibers without cutting, shearing, or removing the structural fibers (possibly except for a very limited number of structural fibers, especially those located at the tip of the tool).

[0013] In US 10315461, all structural fibers set at each perforation to be fabricated are displaced (except that the percentage of structural fibers to be cut is at most equal to 10% of the total structural fibers arranged at each perforation).

[0014] In the solutions described in EP 2422959 and US 10315461, in the case of unidirectional fibers, the displacement of the structural fibers results in the existence of two regions, which include the enrichment of continuous (i.e., uncut) structural fibers arranged in a substantially transverse direction with respect to the perforation seat in a region of opposite diameter. On the other hand, in the case of bidirectional fibers, the displacement of the weft and warp structural fibers results in the existence of four regions, including the enrichment of continuous structural fibers in four regions spaced approximately 90° apart around the perforation seat.

[0015] The applicant has observed that a drawback of the solutions described in EP 2422959 and US 10315461 is that, particularly in the case of unidirectional fibers, and also in the case of bidirectional fibers, due to this fiber displacement, regions consisting only of polymeric material are formed at the relative portions of each perforation, separated from regions containing fiber enrichment. These regions consisting only of polymeric material define structurally weakened portions within the rim. Within these regions, there may also be small portions lacking polymeric material, i.e., portions with air bubbles, resulting in further weakening of the rim.

[0016] Another drawback of the solutions described in EP 2422959 and US 10315461 relates to the fact that the structural fibers around the perforated seat are not fully stretched, and that they must first be stretched and loaded in order to function properly. This results in structural weakening of the rim, or at least a delayed response to the mechanical stresses experienced by the rim during spoke tensioning and during pedaling.

[0017] The fundamental technical problem of this invention is to produce a wheel rim made of composite materials that can better and faster withstand the aforementioned mechanical stresses. Summary of the Invention

[0018] A first aspect of the present invention relates to a bicycle rim comprising a wall formed of a composite material having a plurality of perforated spoke attachment seats, wherein at least one of the perforated seats is defined at least partially by: - At least one first region, which includes the end portions of a first plurality of cut structural fibers; - At least one second region, which is circumferentially spaced from the at least one first region, and includes end portions of a second plurality of cut structural fibers and a first portion of a continuous structural fiber, wherein the longitudinal dimension of the second plurality of cut structural fibers is greater than the longitudinal dimension of the structural fiber of the first plurality of cut structural fibers; At least some of the end portions of the second plurality of cut structural fibers are in a state of being parallel to or interposed to each other relative to the first portion of the continuous structural fiber.

[0019] The following definitions apply in this specification and the attached requests.

[0020] The term "mutually adjacent state" is used to indicate that the relative positions of the first part of the continuous structural fiber and the end portions of the structural fibers of the second plurality of cut structural fibers are such that the end portions of the structural fibers of the second plurality of cut structural fibers are radially adjacent to the first part of the continuous structural fiber, and also indicates that the relative positions of the first part of the continuous structural fiber and the end portions of the structural fibers of the second plurality of cut structural fibers are such that the first part of the continuous structural fiber is radially adjacent to the end portions of the structural fibers of the second plurality of cut structural fibers.

[0021] The term "interlocking state" is used to indicate the relative positions of the first portion of the continuous structural fiber and the end portions of the structural fibers of the second plurality of cut structural fibers, such that the end portions of the structural fibers of the second plurality of cut structural fibers are radially interlocked between the first portions of the continuous structural fiber, and / or vice versa.

[0022] When referring to structural fibers, the term "radial" refers to a direction along an arbitrary radius of the circumference that defines the perforated spoke attachment. Such a direction is also known as the "radial direction".

[0023] When referring to structural fibers, the term "radial outward" indicates a radial direction oriented from the center of the aforementioned circumference toward the outer side of that circumference.

[0024] When referring to structural fibers, the term "radial inward" indicates a radial direction oriented from the outer side of the aforementioned circumference toward the center of that circumference.

[0025] When referring to structural fibers, the term "circumferential" refers to the direction along the circumference of the circle that defines the perforated spoke attachment.

[0026] Advantageously, the wheel rim of the present invention is able to respond to mechanical stresses experienced during use more quickly and efficiently than the wheel rims described in EP 2422959 and US 10315461. This is because structural fiber portions are provided in all areas around each perforated seat, thus providing structural fiber portions also in those areas where the fibers have been displaced and only polymeric material remains, as in the wheel rims described in EP 2422959 and US 10315461.

[0027] In particular, due to the parallel or interlocking of the end portions of the cut structural fibers and the portions of the continuous structural fibers, once the composite material is cross-linked after molding, the end portions of the cut structural fibers are constrained to the continuous structural fibers, thereby contributing to the structural strength of the rim at the perforated spoke attachment.

[0028] In fact, the rim of the present invention has a region enriched with both the end portions of the cut structural fibers and the portions of the continuous structural fibers around the perforated spoke attachments. This region of enriched fibers allows the rim to effectively withstand and transfer the stress experienced at the perforated spoke attachments. In particular, in the aforementioned region of enriched fibers, mechanical stress is gradually and continuously transferred from the end portions of the cut structural fibers to the continuous structural fibers, which is beneficial to the structural strength of the rim.

[0029] In this specification and the accompanying claims, the term "structural fiber enriched region" is used to refer to a region where the local density of structural fibers is greater than the average nominal density of structural fibers in the composite material. Therefore, if the composite material has a certain average nominal density of structural fibers, then in each region of the rim wall away from the perforated spoke attachment, the density of structural fibers is within a tolerance range near the average nominal density, and in the structural fiber enriched region, the density of structural fibers is greater than the upper limit of that tolerance range. The structural fiber enriched region is obtained before molding the composite material, i.e., during the fabrication of the spoke attachments before the composite material crosslinks. In practice, in this case, the structural fibers are able to displace relative to the polymer material because the tools used to fabricate the perforated spoke attachments exert a pushing force on them.

[0030] Preferably, the structural fibers provided in the at least one first region are only those of the first plurality of cut structural fibers. These structural fibers occupy those regions of the rim described in EP 2422959 and US 10315461 (in which the structural fibers have been displaced, leaving only polymeric material), which contributes to the structural strength of the rim in those regions.

[0031] In a first embodiment of the wheel rim of the present invention, the at least one second region includes at least one first region and at least one second region, wherein the at least one first region is provided with the end portions of the second plurality of cut structural fibers and the first portion of the continuous structural fibers, and wherein the at least one second region is provided with only the second portion of the continuous structural fibers.

[0032] In this case, preferably, the at least one first region is interposed circumferentially between the at least one first region and the at least one second region.

[0033] In a second embodiment of the wheel rim of the present invention, only the end portions of the second plurality of cut structural fibers and the first portions of the continuous structural fibers are provided in the at least one second region. Therefore, in this case, there is no region around the perforated spoke attachment where only the portion of the continuous structural fibers is provided.

[0034] In some embodiments of the wheel rim of the present invention, at least some of the end portions of the second plurality of cut structural fibers are arranged at least partially in a radially outer position relative to the first portion of the continuous structural fibers.

[0035] In other embodiments of the wheel rim of the present invention, at least some of the end portions of the second plurality of cut structural fibers are arranged at least partially in a radially inward position relative to the first portion of the continuous structural fiber.

[0036] In a further embodiment of the wheel rim of the present invention, at least some of the end portions of the second plurality of cut structural fibers are arranged radially inward relative to the first portion of the continuous structural fiber, and are arranged radially outward relative to the first portion of the continuous structural fiber.

[0037] In this last case, preferably, the portion of the cut structural fiber arranged in the radially inner position is adjacent to the first region, and the portion of the cut structural fiber arranged in the radially outer position is arranged on the side opposite to the first region with respect to the aforementioned portion of the cut structural fiber arranged in the radially inner position.

[0038] Preferably, at least some of the end portions of the second plurality of cut structural fibers are combined together to form corresponding strands of the cut structural fibers. Advantageously, the cut structural fibers are enriched at such strands, which increases the contribution of the end portions of the cut structural fibers to the strength of the wheel rim structure.

[0039] In a preferred embodiment of the wheel rim of the present invention, the at least one perforated seat is defined at least partially by two first regions and two second regions.

[0040] Preferably, the two second regions are arranged in a first angular sector opposite to the at least one perforated seat.

[0041] In this specification and the accompanying claims, the term "angular sector" is used to refer to an angular portion of the circumference that defines the perforated spoke attachment, such angular portion having an angle of less than 180° relative to the center, preferably less than or equal to 90°.

[0042] The first angular sector can be opposite to the diameter plane of the perforated seat, but not aligned along a specific direction.

[0043] Preferably, the first angular sectors are diametrically opposed, that is, diametrically opposed with respect to the diameter plane of the perforation seat, and aligned in the radial direction.

[0044] Preferably, the two first regions are arranged in a second angular sector opposite to the at least one perforated seat.

[0045] The second angular sector can be opposite to the radial plane of the perforated seat, but not aligned along a specific direction.

[0046] Preferably, the second angular sectors are diametrically opposed, that is, diametrically opposed with respect to the diameter plane of the perforation seat, and aligned in the radial direction.

[0047] Preferably, the two first regions are arranged along a first direction.

[0048] Preferably, in the region away from the perforation seat, the first direction is substantially parallel to the longitudinal direction of the continuous and cut structural fibers.

[0049] Preferably, the two second regions are arranged along a second direction inclined at a first angle about the first direction.

[0050] Preferably, the second direction is substantially perpendicular to the first direction.

[0051] In some embodiments of the wheel rim of the present invention, particularly when at least two second regions are provided, each of the at least two second regions includes the at least one first region and the at least one second region, wherein two diametrical planes of the first region about the perforated seat are arranged on opposite sides.

[0052] In some cases, the aforementioned two first regions are arranged on opposite sides of the diameter plane of the perforated seat, i.e., they are arranged along a single radial direction. In this case, the two first regions are aligned along a cooperating direction, which is preferably inclined at a second angle lower than the first angle relative to the first direction.

[0053] In the above case, preferably, the two in the second region are arranged along the second direction on opposite sides of the perforated seat.

[0054] Preferably, in the region away from the perforation seat, the space occupied by the structural fibers of the first plurality of cut structural fibers and the second plurality of cut structural fibers has a dimension greater than 10% of the diameter of the perforation seat along a direction perpendicular to the longitudinal direction. More preferably, the dimension is between 20% and 70% of the diameter of the perforation seat, including extreme values. In particular, the aforementioned dimension preferably includes between 20% and 50% of the aforementioned diameter, including extreme values.

[0055] In its second embodiment, the present invention relates to a method for manufacturing a bicycle rim, comprising: - The composite material is arranged in a mold, the mold including a radial outer wall having a plurality of first through holes; - By using a cutting tool to pierce the composite material at the plurality of first through holes, a plurality of second through holes are created in the composite material; - Insert the corresponding non-cutting pointed tool into the first and second through holes on the radially inner side of the mold along the corresponding insertion direction until the tip of each non-cutting pointed tool protrudes radially outward relative to the composite material; - The composite material is pressed against the radial outer wall using a pressing tool, and the composite material is compacted at each of the second through holes; - Move each non-cutting tip tool in the opposite direction to the corresponding insertion direction, and remove the non-cutting tip tool from the first through hole; - Molding the composite material in a mold to obtain a corresponding perforated spoke attachment at each of the second through holes; At least one of the perforated seats is defined at least in part by the following: - At least one first region comprising the end portions of a first plurality of cut structural fibers; - At least one second region, which is circumferentially spaced from the at least one first region, and includes two end portions of a second plurality of cut structural fibers and a first portion of a continuous structural fiber, wherein the longitudinal dimension of the second plurality of cut structural fibers is greater than the longitudinal dimension of the structural fiber of the first plurality of cut structural fibers;

[0056] At least some of the end portions of the second plurality of cut structural fibers are in a state of being parallel to or interposed to each other relative to the first portion of the continuous structural fiber.

[0057] In this specification and the attached requests, the terminology is: - "Cutting tool" is used to refer to a rotary tool with at least one cutting edge, such as a drill bit; - "Perforation" is used to describe the mechanical operation of forming cut, continuous structural fibers.

[0058] The bicycle rim according to the first embodiment of the present invention can be manufactured using the aforementioned method. Therefore, this method makes it possible to achieve the advantages described above regarding the rim according to the present invention.

[0059] In particular, compacting the composite material at each of the second through holes makes it possible to obtain the desired state in which the end portions of the cut structural fibers and the first portions of the continuous structural fibers are arranged side by side or interlocked with each other, thereby improving the structural strength of the wheel rim.

[0060] Preferably, the tip is heated. This arrangement makes it possible to increase the displacement capacity and velocity of the structural fibers encountered by the non-cutting tip tool during its movement within the second through-hole.

[0061] Preferably, the compacted composite material includes: - Install the corresponding plug-in program onto each of the aforementioned tips; - The composite material is pressed against the radial outer wall by applying the pressing tool to the external program.

[0062] Therefore, the aforementioned tip serves as a reference and guide for applying and correctly positioning the corresponding external program on the wheel rim being manufactured.

[0063] Subsequently, the add-on was co-molded with the composite material to increase the structural strength of the rim at the perforated spoke attachments and to achieve a more uniform distribution of stress on the rim at these perforated attachments. Furthermore, the co-molding of the add-on prevented frictional wear caused by the add-on sliding on the composite material.

[0064] Preferably, the pressing tool includes a first end portion having a top surface configured to be struck with a hammer.

[0065] Preferably, the pressing tool includes a second end portion having a hollow cylindrical shape.

[0066] Preferably, pressing the composite material against the radial outer wall includes fitting the second end portion onto the tip of each non-cutting tool until the second end abuts against the corresponding attachment. Thus, the aforementioned tip serves as a reference and guide for the pressing tool, thereby facilitating the correct positioning of the second end portion of the pressing tool on the corresponding attachment, and thus aiding in the application of the attachment to the wheel rim being manufactured.

[0067] Preferably, perforating the composite material involves inserting a cutting tool into the first through hole from the radially inner side of the mold along the insertion direction at each of the first through holes.

[0068] Preferably, perforating the composite material includes, after the aforementioned insertion, pushing the cutting tool along the insertion direction until a corresponding second through hole is formed in the composite material.

[0069] Advantageously, the second through hole is formed at the first through hole of the mold.

[0070] The movement of the cutting tool is therefore guided by the aforementioned first through hole. In other words, the first through hole of the mold clearly defines the position and orientation of the piercing seat, making the piercing operation extremely fast and precise.

[0071] Preferably, the mold has a generally annular shape and includes a circumferential groove on its radially inner surface that connects to the first through hole.

[0072] Preferably, the method according to the invention includes inserting a cutting tool into a circumferential groove after the composite material has been arranged in the mold and before perforating the composite material to make each second through hole, and moving the cutting tool along the circumferential groove until reaching the corresponding first through hole. Thus, the cutting tool is easily guided between the first through holes by the circumferential groove. This arrangement helps to make the perforation operation fast and precise.

[0073] Preferably, perforating the composite material includes removing the cutting tool from the second through hole by moving the cutting tool along a second direction opposite to the first direction after pushing the cutting tool along the first direction.

[0074] Preferably, the cutting tool includes a cylindrical cutting section and a conical cutting tip.

[0075] Advantageously, the conical sharp tip allows for precise initiation of drilling, while the cylindrical cut defines the diameter of the second hole, calibrating it to the desired size.

[0076] Preferably, the diameter of the cylindrical cut portion is between 20% and 100% of the diameter of the second through hole, and more preferably between 20% and 70% of the diameter of the second through hole.

[0077] The applicant has observed that, even when the diameter of the cylindrical cut portion is equal to the diameter of the second through-hole, a certain percentage of the structural fibers are not cut (uncut) but rather displaced. This displacement is initially caused by the conical cut tip and subsequently by the cylindrical cut portion, as the cutting tool operates on uncrosslinked polymeric material, thus allowing the structural fibers contained therein to displace.

[0078] According to a preferred embodiment of the method of the present invention, the conical cutting tip is a diamond-set tip.

[0079] Advantageously, the tip of the diamond-set end has significant characteristics in terms of cutting reliability and durability.

[0080] Preferably, each of the non-cutting pointed tools includes a cylindrical portion and a conical non-cutting tip.

[0081] Preferably, the diameter of the cylindrical portion is between 90% and 100% of the diameter of the second through hole, more preferably between 95% and 100% of the diameter of the second through hole, and even more preferably between 97% and 100% of the diameter of the second through hole, for example, equal to 98% of the diameter of the second through hole. Simple Explanation of the Diagram

[0082] Referring to the accompanying drawings, other features and advantages of the invention will become more apparent from the description of preferred embodiments thereof, wherein:

[0083] Figure 1 schematically illustrates a perspective view of a bicycle rim according to the present invention;

[0084] Figure 2 schematically illustrates a plan view of a portion of a composite material disposed in a prior art bicycle rim;

[0085] Figure 3 schematically illustrates a plan view of a portion of the composite material disposed in a first preferred embodiment of the wheel rim according to the present invention;

[0086] Figure 4 schematically illustrates a plan view of a portion of the composite material disposed in a second preferred embodiment of the wheel rim according to the present invention;

[0087] Figure 5 schematically illustrates a perspective view of the first manufacturing step of a bicycle rim according to the method of the present invention;

[0088] Figure 6 schematically illustrates a partial cross-sectional top side view of the manufacturing steps in Figure 5;

[0089] Figure 7 schematically illustrates a perspective view of the cutting tool used in the manufacturing steps of Figure 5;

[0090] Figure 8 schematically illustrates a partial cross-sectional top side view of a second manufacturing step according to the method of the present invention, which follows the step in Figure 5;

[0091] Figure 9 schematically illustrates a perspective view of the third manufacturing step according to the method of the present invention, which follows the step in Figure 8;

[0092] Figure 10 schematically illustrates a perspective view of the fourth manufacturing step according to the method of the present invention, which follows the step in Figure 9. Implementation

[0093] Referring first to Figure 1, the bicycle rim according to the present invention is generally represented by 50. The bicycle wheel is represented by 55.

[0094] The wheel rim 50 is at least partially made of composite material 6.

[0095] The structural fibers of composite material 6 are preferably selected from carbon fiber, glass fiber, boron fiber, aramid fiber, ceramic fiber and combinations thereof, with carbon fiber being preferred.

[0096] The polymeric material of composite material 6 can be thermoplastic or thermosetting. Preferably, the polymeric material is a thermosetting resin.

[0097] The mechanical properties of composite material 6 can vary depending on the type of structural fiber, the type of weaving / arrangement, the type of polymer, and the percentage of structural fiber to polymer.

[0098] In the non-restrictive cases shown in Figures 3 and 4, the structural fibers of composite material 6 are unidirectional fibers.

[0099] Figures 3 and 4 illustrate a portion of the layers of unidirectional structural fiber 60. The structural fibers of composite material 6 can also be arranged in many side-by-side layers.

[0100] In Figures 3 and 4, the unidirectional structural fibers 60 extend substantially parallel to each other along the longitudinal direction L, which may be parallel or inclined relative to the circumferential direction of the rim 50.

[0101] Preferably, a plurality of unidirectional fiber layers are provided side by side, the layers being arranged such that the directions of the unidirectional fibers of two adjacent layers form an angle with opposite signs to the circumferential direction of the rim 50, and preferably +45° and -45°.

[0102] The rim 50 has a predetermined axis of rotation X and is mounted on the hub 54 of the bicycle wheel 55 by a plurality of spokes 52.

[0103] The rim 50 has a radially inner annular wall 56 made of a composite material. A plurality of perforated spoke attachment seats 58 are formed on such annular wall 56, the plurality of perforated spoke attachment seats 58 preferably having a substantially circular shape, and spokes 52 are mounted at the plurality of perforated spoke attachment seats 58.

[0104] The wheel rim 50 has a radially outer annular wall 57, which has a plurality of through holes 57a, each through hole 57a located at a corresponding perforated seat 58.

[0105] In the non-limiting example of Figure 1, the annular wall 56 has a shape symmetrical about the axis of rotation X and a diameter intermediate plane perpendicular to the axis of rotation X, and the spokes 52 extend along a generally radial direction. However, alternative embodiments are provided in which the annular wall 56 has an asymmetrical shape and / or the spokes 52 extend in a direction inclined about the radial direction.

[0106] In this specification and the accompanying claims, the terms "inner" and "outer" refer to the radial direction of the rim 50, or in some cases, they may refer to the direction occupied by the spokes 52. In any case, the foregoing terms are used to indicate the position of the rim 50 in the proximal and distal directions, respectively, with respect to the axis of rotation X of the rim 50.

[0107] Figure 2 schematically illustrates, as an example, the progress of unidirectional fibers approaching a perforated spoke attachment 58a of a bicycle rim, according to prior art similar to the aforementioned documents EP 2422959 and US 10315461. The perforated attachment 58a is formed by displacement of the unidirectional structural fibers 40 prior to molding the composite material.

[0108] In particular, it is noted that there are two regions 42 enriched with continuous unidirectional structural fibers 40. The two regions 42 are arranged in diameter opposite portions with respect to the perforation seat 58a, and in the region away from the perforation seat 58a, they are arranged in a transverse direction T that is substantially perpendicular to the longitudinal direction L of the unidirectional structural fibers 40.

[0109] It is also noted that there are two regions 44, one containing only polymeric material and the other containing no polymeric material in the cells 46. Regions 44 are arranged in opposite portions about each perforation seat 58a and are spaced approximately 90° from the region 42 where fibers 40 are enriched.

[0110] Figures 3 and 4 schematically illustrate, as examples, the progress of the perforated seat 58 of the annular wall 56 of two preferred embodiments of the structural fiber near the rim 50.

[0111] In the non-limiting examples of Figures 3 and 4, the composite material includes unidirectional structural fibers 60 that extend along a longitudinal direction L in a region away from the perforated seat 58. The longitudinal direction L may be parallel to or inclined about the circumferential direction of the rim 50, for example, at approximately 45° or approximately 60°.

[0112] Each perforated seat 58 has a substantially circumferential shape and is defined along its entire circumference 59 by continuous unidirectional structural fibers 60 and cut unidirectional structural fibers 60.

[0113] In particular, in the first preferred embodiment of the rim 50 shown in FIG3, one or some or each of such perforated seats 58 is defined by two first regions 62 and two second regions 63, the first regions 62 including the end portions of the cut structural fibers 60a, and the second regions 63 including the end portions of the cut structural fibers 60b and portions of the continuous structural fibers 60c.

[0114] The longitudinal dimension of the cut structural fiber 60b is larger than that of the cut structural fiber 60a, and it can be in a parallel state relative to the portion of the continuous structural fiber 60c, or in a state of interleaving with the portion of the continuous structural fiber 60c.

[0115] In particular, at least some of the end portions of the cut structural fibers 60b may be arranged in a radially outer position relative to a portion of the continuous structural fibers 60c, or in a radially inner position relative to a portion of the continuous structural fibers 60c, or partially arranged in a radially outer position relative to a portion of the continuous structural fibers 60c and partially arranged in a radially inner position relative to a portion of the continuous structural fibers 60c, or they may be inserted between portions of the continuous structural fibers 60c.

[0116] Typically, at least some of the end portions of the cut structural fiber 60b may have portions arranged in a radially inward position and / or a radially outward position and / or inserted relative to portions of the continuous structural fiber 60c.

[0117] Furthermore, at least some of the end portions of the cut structural fiber 60b can be combined together to form corresponding strands of the cut structural fiber.

[0118] In the non-limiting example of Figure 3, the structural fibers provided in the first region 62 are only the structural fibers of the first plurality of cut structural fibers 60a, while in the second region 63, only the end portions of the cut structural fibers 60b and portions of the continuous structural fibers 60c are provided. Therefore, the peripheral circumference 59 of the perforated seat 58 does not have a portion that only provides the portion of the continuous structural fibers 60c.

[0119] Specifically, referring to Figure 3, around the perforated seat 58, at the upper right and lower left, the two end portions of the cut structural fiber 60b cross the entire second region 63 at the top (from left to right) and at the bottom (from right to left). In other words, by drawing two vertical diameter planes in Figure 3 extending along the longitudinal direction L and the transverse direction T perpendicular to the longitudinal direction L, and by identifying the four angular sectors around the perforated seat 58 located in the corresponding quadrants represented by Q1-Q4 (moving clockwise from the upper left angular sector), the two end portions of the cut structural fiber 60b cross the entire second region 63 at the top from quadrant Q1 to quadrant Q2, and the other two end portions of the cut structural fiber 60b cross the entire second region 63 at the bottom from quadrant Q3 to quadrant Q4.

[0120] The second region 63 is separated from the first region 62 in the circumferential direction.

[0121] In the non-limiting example shown in Figure 3, two first regions 62 are arranged on opposite sides of the perforation seat 58 along the longitudinal direction L, and two second regions 63 are arranged on opposite sides of the perforation seat 58 along the transverse direction T. Therefore, the two first regions 62 are opposite each other diametrically and are spaced approximately 90° apart with respect to the two second regions 63.

[0122] As shown in Figure 3, in the region away from the perforation seat 58, the longitudinal direction L is basically parallel to the longitudinal direction of the continuous structural fiber 60c and the cut structural fibers 60a and 60b.

[0123] It should also be noted that some of the cut structural fibers 60a in the first region 62 have a curved shape near the perforation seat 58, while in the region away from the perforation seat 58, they have a substantially straight shape and are parallel to the longitudinal direction L. Near the peripheral circumference 59 of the perforation seat 58, the cut structural fibers 60a tend to open with respect to the diametrical plane A of the perforation seat 58, which is parallel to the longitudinal direction L; that is, they exhibit a gradually increasing inclination with respect to the longitudinal direction L as the second region 63 and therefore the perforation seat 58 approach. Similarly, some of the cut structural fibers 60b in the second region 63 also open with respect to the diametrical plane A of the perforation seat 58.

[0124] In the region away from the perforation seat 58, the cut structural fibers 60a and 60b occupy a space with a transverse dimension T greater than 10% of the diameter D of the perforation seat 58. Preferably, such a dimension is between 20% and 70% of the diameter D of the perforation seat 58, including extreme values, and more preferably between 20% and 50% of the diameter D.

[0125] Figure 4 illustrates a second embodiment of the wheel rim 50 according to the present invention, which differs from the embodiment of Figure 3 only in the type of structural fibers disposed in the second region 63.

[0126] Specifically, in the embodiment of FIG4, each of the two regions 63 includes a first region 63' and a second region 63'', wherein the first region 63' provides the end portion of the cut structural fiber 60b and the first portion of the continuous structural fiber 60c, and the second region 63'' provides only the second portion of the continuous structural fiber 60c.

[0127] The first zone 63' is inserted circumferentially between the first zone 62 and the second zone 63''.

[0128] The two first regions 63' of the two second regions 63 are arranged on opposite sides of the diameter at an angle between 15° and 45° with respect to the perforated seat 58, with an inclination of less than 90° relative to the longitudinal direction L.

[0129] The two second regions 63'' are arranged on opposite sides of the diameter along the transverse direction T with respect to the perforated seat 58.

[0130] In the non-limiting example of Figure 4, there are two first regions 63' and one second region 63'' in quadrants Q1 and Q2, and in quadrants Q3 and Q4. Therefore, unlike the embodiment of Figure 3, there is no end portion of the cut structural fiber 60b that crosses the second region 63.

[0131] Further embodiments are provided, wherein, for example, a first region 63' is located in quadrant Q1 (and / or quadrant Q3) and a second region 63'' is located in quadrant Q2 (and / or quadrant Q4).

[0132] Referring to Figures 5-10, a preferred embodiment of the method for manufacturing bicycle rims, such as the rim 50 described above, according to the present invention is illustrated.

[0133] The method involves molding the composite material in mold 70.

[0134] The mold 70 has a substantially annular shape and includes two annular elements 1 and 2 joined together to define the mold cavity 3.

[0135] In the embodiment shown in the accompanying drawings, the mold cavity 3 is shaped to manufacture a symmetrical rim 50, particularly for tubeless tires.

[0136] When connected, the annular elements 1 and 2 define a plurality of through holes 5, and the through hole seat 58 is made at the plurality of through holes 5.

[0137] Figure 6 shows the right half of the mold 70 cut at through hole 5.

[0138] In the embodiment shown in the accompanying drawings, the through hole 5 is partially formed in the annular element 1 and partially formed in the annular element 2, and includes a substantially cylindrical radially outer portion 5a and a radially inner portion 5b, the radially inner portion 5b having an inwardly flared substantially truncated conical or cylindrical shape.

[0139] The diameter of the radial outer portion 5a is substantially equal to, or slightly larger than, the nominal diameter D of the perforated spoke attachment 58.

[0140] The radially outer portion 5a extends in a direction corresponding to the direction in which the spokes 52, housed in the perforated seat 58 of the rim 50, extend.

[0141] In the case shown in the accompanying drawings, this direction extends in the plane of Figure 5 (i.e., in the transverse plane of the rim 50) along a direction inclined about the diameter mid-plane Y of the mold 70. Therefore, the corresponding spokes 52 are of the type constructed to be radially attached to the hub 54 with a certain camber. Those skilled in the art will understand that other through-holes 5 are positioned appropriately along the circumferential direction of the annular elements 1 and 2, and the appropriate inclination of the relevant radially outer portion 5a depends on the desired camber angle.

[0142] Because in some spoke arrangements, the perforated seat 58 in the rim 50 may not be aligned along a single midplane of the rim 50, and / or the spoke 52 may be tangential to the hub 54 or, in either case, non-radially attached to the hub 54, the through holes 5 in the annular elements 1 and 2 will have appropriate orientation and position, and some through holes 5 may also extend only in one of the annular elements 1 and 2.

[0143] The annular elements 1 and 2 preferably have abutment members (not shown), such as pins and centering holes, reference marks, etc., to ensure that when they are joined together, the two portions of the through holes 5 of each of the two annular elements 1 and 2 are properly aligned to fully define the through hole 5 itself.

[0144] The mold 70 includes a circumferential groove 72 connected to the through hole 5 on its radial inner surface 71.

[0145] The method according to the invention initially involves arranging the composite material 6 in a mold 70, particularly on the radial outer wall 3a of the mold cavity 3.

[0146] More specifically, the mold cavity 3 is coated with one or more layers of sheet composite material 6, preferably pre-impregnated. This material is commonly referred to in the art as sheet molding compound (SMC) or "prepreg" and essentially comprises structural fibers pre-impregnated with polymeric material.

[0147] The arrangement of composite material 6 in mold cavity 3 can be done manually or automatically.

[0148] The composite material 6 is perforated at the through hole 5 by the cutting tool 80 shown in Figure 7.

[0149] The cutting tool 80 is a rotary tool mounted on an angle screwdriver 90 (as shown in Figures 5 and 6) or a drill bit. The angle screwdriver 90 has the advantage of being easy to operate in confined spaces (such as the space inside the mold 70).

[0150] In the non-limiting example shown in Figure 7, the cutting tool 80 includes a cylindrical shank 81 with a cylindrical cutting portion 84 and a conical cutting tip 86 at its free end. Both the cylindrical cutting portion 84 and the conical cutting tip 86 have at least one cutting edge 82.

[0151] In the specific example shown here, there is more than one cutting edge 82 (e.g., four), and they extend flawlessly over the cylindrical cutting portion 84 and the conical cutting tip 86.

[0152] Preferably, the tapered cutting tip 86 is a diamond-set tip.

[0153] The perforation of the composite material 6 by the cutting tool 80 creates a through hole 6a in the composite material 6 at each through hole 5 of the mold 70.

[0154] The diameter of the cylindrical cutting portion 84 of the cutting tool 80 is selected as a function of the diameter of the through hole 6a to be formed, a function of the desired ratio between the cut and continuous (uncut) structural fibers obtained at the through hole 6a, and selected from industrial evaluations (requiring no damage to the cutting tool 80 and processing time).

[0155] Preferably, the diameter of the cylindrical cut portion 84 is between 20% and 100% of the diameter of the through hole 6a, more preferably between 20% and 70% of the diameter of the second through hole 6a. During perforation, a portion of the structural fiber will shift because it has not yet been blocked by the cross-linked polymeric material.

[0156] For example, to create a through hole 6a with a diameter of 5 mm, a cutting tool 80 with a cylindrical cutting portion 84 having a diameter of 3.5 mm can be used.

[0157] Preferably, the cutting tool 80 is used at room temperature, i.e., without heating before use, to avoid the sheared structural fiber portions remaining adhered to its surface, which would degrade the quality and dimensional accuracy of the through hole 6a.

[0158] The process of perforating the composite material 6 to form through holes 6a initially involves inserting a conical cutting tip 86 into a circumferential groove 72, and then moving the cutting tool 80 along the circumferential groove 72 until each through hole 5 is reached.

[0159] Once the through hole 5 is reached, the cutting tool 80 is inserted into it along the first direction F, starting from its radially inner portion 5b. The generally truncated conical (or cylindrical) shape of the radially inner portion 5b makes the insertion of the cutting tool 80 easier and guides it.

[0160] Subsequently, the cutting tool 80 reaches the generally cylindrical radially outer portion 5a of the through hole 5 and is pushed until it reaches the composite material 6, perforating the composite material 6 and thus creating a through hole 6a in the composite material 6. In the non-limiting example shown, the cutting tool 80 is configured to rotate in a clockwise direction.

[0161] Then, move the cutting tool 80 in the opposite direction B to the insertion direction F, and remove the cutting tool 80 from the through hole 5.

[0162] The conical tip 86 of the cutting tool 80 thus moves at the circumferential groove 72 and runs across the groove 72 until it reaches the next through hole 5, where it pierces the composite material 6 in the same manner as described above.

[0163] After the cutting tool 80 is removed from the through hole 6a, as shown in Figure 9, the through hole 6a is finished to size by means of a non-cutting pointed tool 8, such as a pin.

[0164] In this specification, the term "dimension finishing" refers to a mechanical operation that causes the cutting structural fibers 60a, 60b and the continuous structural fibers 60c to be displaced until the desired size of the through-hole 6a in the composite material 6 is achieved. This through-hole 6a defines the nominal design size of the perforated spoke attachment 58 after the composite material 6 is molded. In the case of pre-impregnated structural fibers, the polymer material 6 is also displaced by a non-cutting tip tool 8.

[0165] As shown in Figure 9, it is preferable to provide a plurality of non-cutting pointed tools 8 so that they can be operated in series on a plurality of perforation seats 58.

[0166] Each non-cutting tip tool 8 includes a cylindrical portion 8a and a conical (or truncated conical) non-cutting tip 8b.

[0167] The diameter of the cylindrical portion 8a corresponds substantially to the nominal diameter D of the perforated spoke attachment 58 to be formed in the rim 50, or it is slightly larger than such nominal diameter D.

[0168] The diameter of the cylindrical portion 8a is substantially equal to or slightly smaller than the diameter of the radially outer portion 5a of the through hole 5.

[0169] The diameter of the cylindrical portion 8a is between 90% and 100% of the diameter of the through hole 6a, preferably between 95% and 100% of the diameter of the through hole 6a, and even more preferably between 97% and 100% of the diameter of the through hole 6a, for example, equal to 98% of the diameter of the through hole 6a.

[0170] The non-cutting pointed tool 8 is inserted into the through hole 6a from the through hole 5 along the first direction F, thereby being inserted from the radially inner side of the mold 70 (Figures 9 and 10). This insertion is made easier by the generally truncated conical shape and inwardly flared shape of the radially inner portion 5b of the through hole 5.

[0171] Then, the non-cutting tip tool 8 reaches the radially outer portion 5a of the through hole 5 and is pushed until the non-cutting tip tool 8 reaches and passes through the through hole 6a, thereby dimensionally finishing it. Thus, the insertion of the non-cutting tip tool 8 continues until a portion of the conical non-cutting tip 8b and the cylindrical portion 8a protrudes radially outward relative to the composite material 6.

[0172] As shown in Figure 10, the non-cutting pointed tool 8 may include an abutting shoulder 8c configured to abut against the radially inner surface 71 of the mold 70 at the through-hole 5, so as to easily define the correct insertion depth of the non-cutting pointed tool 8 in the mold 70. This abutting shoulder 8c is defined at the end of the gripping portion 8d of the non-cutting pointed tool 8, which is located radially inward relative to the cylindrical portion 8a of the non-cutting pointed tool 8.

[0173] The insertion of a non-cutting pointed tool 8 into the through-hole 6a of the composite material 6 causes displacement of the continuous structural fibers 60c and the cut structural fibers 60a, 60b until the desired size of the through-hole 6a is achieved. This desired size defines the nominal design size D of the perforation seat 58 after subsequent molding of the composite material 6. Typically, the diameter of the dimensionally finished through-hole 6a created by the non-cutting pointed tool 8 is greater than or equal to the diameter of the through-hole 6a after perforation by the cutting tool 80, the latter depending on the diameter of the cylindrical cutting portion 84 of the cutting tool 80.

[0174] In the aforementioned insertion step of the non-cutting pointed tool 8, the non-cutting pointed tool 8 follows the inclination of the radially outer portion 5a of the through hole 5 in the inner elements 1 and 2 of the mold 70. Therefore, the through hole 5 serves as a guide for the non-cutting pointed tool 8.

[0175] Preferably, the non-cutting tip tool 8 is used after at least the conical non-cutting tip 8b has been heated. In this case, at the conical non-cutting tip 8b, the viscosity of the polymeric material decreases, promoting the displacement of the continuous structural fiber 60a and the cut structural fibers 60b, 60c.

[0176] Preferably, if the polymer of composite material 6 is thermosetting, the temperature of the pointed tool 8 is below its crosslinking temperature. However, the temperature of the pointed tool 8 can also be above the crosslinking temperature. In this case, the time the pointed tool 8 remains in the through-hole 6a of composite material 6 is reduced, thus preventing the temperature of composite material 6 from rising to the crosslinking temperature. Heating must also be carried out at a temperature that prevents the polymer from dripping into the through-hole 5. By way of example only, the heating temperature can be between 80° and 100°.

[0177] The insertion of the non-cutting pointed tool 8 into the composite material 6 ensures that some end portions of the cut structural fiber 60b protrude from the through hole 6a toward the cavity 3 of the mold 70.

[0178] Therefore, the composite material 6 is subsequently compacted at each through-hole 6a. This compaction ensures that the aforementioned end portions of the cut structural fibers 60b protruding relative to the through-hole 6a are partially folded toward the continuous structural fibers 60c arranged around the peripheral circumference 59 of the perforation seat 58, preferably producing the aforementioned strands.

[0179] In the non-limiting example shown in the accompanying drawings, the corresponding add-on program 20 is located at each through hole 6a before the non-cutting tip tool 80 is extracted from the through hole 6a and the aforementioned compaction is performed (Fig. 10).

[0180] This plug-in program 20 has a corresponding through hole 20a, which fits onto the conical non-cutting tip 8b and onto the cylindrical portion 8a of each non-cutting tip tool 8 protruding relative to the composite material 6 until it abuts against the composite material 6.

[0181] In terms of fatigue resistance and co-molding capability with composite material 6, the outer program 20 is made of a material with good properties. Fiber-reinforced thermoplastic or thermosetting polymers and metallic materials are suitable. A particularly preferred material is polyetherimide, specifically Ultem 2400 sold by Sabic in Riyadh, Saudi Arabia.

[0182] Then, the composite material 6 is compacted at each through hole 6a. This compaction is achieved by pressing the composite material 6 against the radial outer wall 3a of the mold 70 by applying the pressing tool 10 to the external program 20 (Fig. 10).

[0183] The pressing tool 10 includes a first end portion 11 and a second end portion 12. The first end portion 11 has a top surface 11a configured to be struck with a hammer, and the second end portion 12 has a hollow cylindrical shape.

[0184] The cavity of the second end portion 12 has a substantially cylindrical wall 12a, and its dimensions are adapted to fit onto the conical non-cutting tip 8b of the non-cutting tip tool 8 and onto the portion of its cylindrical portion 8a located in the cavity 3 of the mold 70 (FIG. 10). In particular, the second end portion 12 is fitted onto the free end of the non-cutting tip tool 8 until its free end surface 12b abuts against the attachment 20.

[0185] The top surface 11a of the compaction tool 10 is thus hammered. Due to this hammering, the radial inner surface 20b of the outer program 20 presses against the underlying composite material 6 portion, performing the aforementioned compaction.

[0186] Subsequently, the non-cutting tip tool 8 is moved in the opposite direction B to the insertion direction F, and removed from the through hole 5. Due to the aforementioned compaction, the external program 20 remains associated with the perforation seat 58 and is then at least partially incorporated into the composite material 6 after subsequent molding.

[0187] After the non-cutting tip tool 8 is removed from the corresponding through hole 6a, the possible end portion of the cut structure fiber protruding from the through hole 6a in the radially inward direction can be removed by finishing.

[0188] Therefore, the molding of the composite material 6 in the mold 70 continues, and a corresponding perforated spoke attachment 58 is obtained at each second through hole 6a.

[0189] During the molding operation, further compaction of the polymer material occurs, and cross-linking of the polymer material occurs if the polymer material is thermosetting, resulting in locking the positions of the continuous structural fiber 60c and the cut structural fibers 60a, 60b, and the external program 20.

[0190] The method described above, whose basic features are set forth in the following claim, enables the production of wheel rims with diameters even greater than 5 mm, such as perforated seats 58 between 5.7 mm and 6.5 mm, with high repeatability.

[0191] Of course, those skilled in the art can make various changes and modifications to this invention to meet specific or particular requirements, all of which are in any case within the scope of protection defined by the appended claims. Therefore, the following is merely an example.

[0192] Instead of using pre-impregnated composite materials, dry fiber materials can be used during the initial steps of the method, thus allowing the perforation step, in particular, to be performed solely on the dry fiber material. Subsequently, polymeric materials are preferably injected at several points to incorporate the dry fiber material, followed by the application of the temperature and pressure distribution required for the hardening of the composite material.

[0193] Furthermore, the method may include a step of temporarily sealing the perforation seat during the aforementioned molding step, for example using an auxiliary element similar to that described in EP 2422959. In any case, the temporary sealing of the perforation seat during molding may be omitted, which can be achieved by specifying a cleaning step after molding.

[0194] The method of the present invention may include the step of co-molding an outer rim component made of metal or composite material with the aforementioned portion of a rim made of composite material.

[0195] The above method can also be applied only to some spoke attachments, while other spoke attachments are formed in the rim using conventional techniques.

[0196] The bicycle rims made according to the present invention are particularly suitable for tubeless wheels.

[0197] However, it should be understood that the present invention is also applicable in its various forms to wheel rims with air chambers and (clamping) wheel rims with tubular tires.

[0198] 1: Internal components 2: Internal components 3: Mold cavity 5: Through hole 6: Composite materials 8: Non-cutting pointed tools 10: Compression tools 11: First end portion 12: Second end portion 20: Plugins 40: Fiber 42: Area 44: Area 46: Cells 50: Bicycle rims 52: Spokes 55: Bicycle wheels 56: wall 57: Radial outer annular wall 58: Perforated spoke attachment 59: Peripheral circumference 60: Unidirectional structural fiber 62: First Area 63: Second Area 70: Mold 71: Radial inner surface 72: Circumferential groove 80: Cutting tools 81: Cylindrical handle 82: Cutting blade 84: Cylindrical cut section 86: Conical cutting tip 90° Angle Screwdriver 11a: Top surface 12a: wall 12b: Free end surface 20a: Through hole 20b: Radial inner surface 3a: Radial outer wall 57a: Through hole 5a: Radial outer portion 5b: Radial inner portion 60a: Cut structural fibers 60b: Cut structural fibers 60c: Structural fiber 63': Zone 1 63'': Second Zone 6a: Through hole 8a: Cylindrical section 8b: Conical non-cutting tip 8c: Abutting the shoulder 8d: Grip portion B: Direction F: Insertion direction L: Vertical direction Q1: Quadrant Q2: Quadrant Q3: Quadrant Q4: Quadrant T: Lateral direction X: Axis of rotation Y: Diameter mid-plane

[0199] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A bicycle rim (50) comprising a wall (56) made of a composite material having a plurality of perforated spoke attachments (58), wherein at least one of the perforated spoke attachments (58) is defined at least partially by: - ​​at least one first region (62) comprising end portions of a first plurality of cut structural fibers (60a); - at least one second region (63) spaced circumferentially from the at least one first region (62), and the at least one second region (63) comprising end portions of a second plurality of cut structural fibers (60b) and a first portion of a continuous structural fiber (60c), wherein a longitudinal dimension of the second plurality of cut structural fibers (60b) is greater than the longitudinal dimension of the structural fiber of the first plurality of cut structural fibers (60a); At least some of the end portions of the structural fibers of the second plurality of cut structural fibers (60b) are in a state of being parallel or interposed to each other relative to the first portion of the continuous structural fiber (60c).

2. The rim (50) according to claim 1, wherein the at least one second region (63) includes at least one first region (63') and at least one second region (63''), wherein the at least one first region (63') is provided with the end portions of the second plurality of cut structural fibers (60b) and the first portion of the continuous structural fiber (60c), and wherein the at least one second region (63'') is provided with only the second portion of the continuous structural fiber (60c).

3. The rim (50) according to claim 1, wherein in the at least one second region (63), only the end portion of the second plurality of cut structural fibers (60b) and the first portion of the continuous structural fibers (60c) are provided.

4. The rim (50) according to claim 1, wherein at least some of the end portions of the second plurality of cut structural fibers (60b) are arranged at least partially in a radially outer position relative to the first portion of the continuous structural fiber (60c).

5. The rim (50) according to claim 1, wherein at least some of the end portions of the second plurality of cut structural fibers (60b) are arranged at least partially in a radially inward position relative to the first portion of the continuous structural fiber (60c).

6. The rim (50) according to claim 1, wherein at least some of the end portions of the second plurality of cut structural fibers (60b) are combined together to form corresponding strands of the cut structural fibers.

7. The rim (50) according to claim 1, wherein the at least one perforated spoke attachment (58) is at least partially defined by two first regions (62) and two second regions (63), wherein the two second regions (63) are arranged in a first angular sector opposite to the at least one perforated spoke attachment (58), and the two first regions (62) are arranged in a second angular sector opposite to the at least one perforated spoke attachment (58).

8. The rim (50) according to claim 7, wherein the two first regions (62) are arranged along a first direction (L) and the two second regions (63) are arranged along a second direction (T) which is substantially perpendicular to the first direction (L).

9. The rim (50) according to claim 8, wherein in the region away from the perforated spoke attachment (58), the first direction is substantially parallel to a longitudinal direction of the continuous structural fiber (60c) and the longitudinal direction of the cut structural fiber (60a, 60b).

10. A method for manufacturing a bicycle rim (50) comprising the following steps: - arranging a composite material (6) in a mold (70) including a radial outer wall (3a) having a plurality of through holes (5); - perforating the composite material (6) at the plurality of through holes (5) by means of a cutting tool (80, thereby creating a plurality of through holes (6a) in the composite material; - inserting corresponding non-cutting pointed tools (8) from a radially inner side of the mold (70) along a corresponding insertion direction (F) into the through holes (5) and the through holes (6a) until a tip (8b) of each non-cutting pointed tool (8) protrudes in a radially outward direction relative to the composite material (6); - compacting the composite material (6) at each of the through holes (6a) by pressing the composite material (6) against the radial outer wall (3a) with a pressing tool (10); The non-cutting tip tool (8) is removed from the through hole (5) by moving each non-cutting tip tool (8) in a direction (B) opposite to the corresponding insertion direction (F); - The composite material (6) is molded in the mold (70) to obtain a corresponding perforated spoke attachment (58) at each through hole (6a); wherein at least one of the perforated spoke attachments (58) is defined at least in part by the following features: - at least one first region (62) comprising the end portions of a first plurality of cut structural fibers (60a); - At least one second region (63) is circumferentially spaced from the at least one first region (62), and the at least one second region (63) includes end portions of a second plurality of cut structural fibers (60b) and a first portion of a continuous structural fiber (60c), wherein a longitudinal dimension of the second plurality of cut structural fibers (60b) is greater than the longitudinal dimension of the structural fiber of the first plurality of cut structural fibers (60a); wherein at least some of the end portions of the structural fibers of the second plurality of cut structural fibers (60b) are in a state of being parallel or interposed to each other relative to the first portion of the continuous structural fiber (60c).

11. The method according to claim 10, wherein the tip (8b) is heated.

12. The method according to claim 10, wherein the step of compacting the composite material (6) includes the following steps: - attaching a corresponding applicator (20) to each of the tips (8b); - pressing the composite material (6) against the radial outer wall (3a) by applying the pressing tool (10) to the applicator (20).

13. The method according to claim 12, wherein the pressing tool (10) includes a first end portion (11) and a second end portion (12), the first end portion (11) having a top surface (11a) configured for being struck with a hammer, the second end portion (12) having a hollow cylindrical shape, and wherein the step of pressing the composite material (6) against the radial outer wall (3a) includes the following steps: fitting the second end portion (12) onto the tip (8b) of each non-cutting tip tool (8) until the second end portion (12) abuts against the corresponding attachment (20).

14. The method according to claim 10, wherein the step of perforating the composite material (6) comprises the following steps: at each of the through holes (5), inserting the cutting tool (80) from the radially inner side of the mold (70) into the through hole (5) along the insertion direction (F), and subsequently pushing the cutting tool (80) along the insertion direction (F) until a corresponding through hole (6a) is formed in the composite material (6).

15. The method of claim 10, wherein the mold (70) has a generally annular shape and the mold (70) includes a circumferential groove (72) connected to the through hole (5) on a radially inner surface (71) of the mold (70), and wherein the method includes the steps of: after the composite material (6) is arranged in the mold (70) and before the composite material (6) is perforated to make each through hole (6a), inserting the cutting tool (80) into the circumferential groove (72) and moving the cutting tool (80) along the circumferential groove (72) until reaching the corresponding through hole (5).

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