Rims, rim components and rim assemblies for bicycle wheels and methods for manufacturing the same

Abstract

A rim assembly for a bicycle wheel is disclosed. The rim assembly includes: a rim configured to receive a rim component in an outer surface of the rim; and a rim component located in the outer surface of the rim, wherein the rim component forms part of the outer surface of the rim, and wherein the rim component has a lower density compared to the rim. Also disclosed are a rim, an insertable rim component, and a method of manufacturing such a rim assembly.

Description

Technical Field

[0001] The present invention relates to a rim and a rim assembly for a bicycle wheel and related manufacturing methods. The present invention also relates to a wheel for a bicycle. Background Art

[0002] Conventional bicycle wheels include a rim, a hub, and a plurality of spokes, wherein the spokes connect the hub to the rim. A bicycle tire is mounted to the rim using a clincher tire configuration, a tubular tire configuration, or a tubeless tire configuration. The wheel is mounted to the bicycle frame at the hub.

[0003] The latest focus in wheel rim technology relates to aerodynamic efficiency, wherein the shape of the rim affects the air flow above the rim surface. More specifically, the focus has been directed to the combination of the rim and the mounted tire, and efforts are being made to reduce the aerodynamic drag caused by the combination of the rim and the tire, thereby allowing the rider to maintain a higher speed.

[0004] FIG. 1 is a schematic cross-sectional view of a conventional rim for a bicycle wheel. The rim 1 is shown with a tire 200 mounted thereon using a clincher tire configuration. The rim 1 includes: opposite first and second sidewalls 3 and 5; a tire mounting portion 10 and a spoke attachment portion 7. The spoke attachment portion 7 includes a plurality of through holes (not shown) such that spokes can be attached to the rim. The spoke attachment portion 7 is located in the radially inner portion of the rim, and the tire mounting portion is located in the radially outer portion of the rim. The space between the opposite first and second sidewalls is generally hollow.

[0005] The tire mounting portion 10 includes opposite first and second wall segments 11 and 12 that extend circumferentially around the outer periphery of the rim. The first and second wall segments form part of the first and second sidewalls of the rim. The first wall segment 11 and the second wall segment 12 each include an inwardly facing hook portion 11a, 12a that is configured to hold the tire bead 201 of a clincher-type tire 200 (or a tubeless-type tire).

[0006] An inner tube 210 is disposed within the mounted clincher-type tire 200, and the inner tube 210 is inflated with air to inflate the tire to the desired pressure. When the tire is mounted and inflated, the nominal width of the tire is represented by the dimension T in FIG. 1.

[0007] Rolling resistance tests of road bicycle tires have shown that when using wider tires (i.e., larger "T") on open roads under non-ideal "real-world" conditions, such tires generally have lower rolling resistance. Typical tire width values for such "wider" tires can range between 25 mm and 40 mm. Such wider tires are also generally more comfortable for cyclists. Using wider tires for road bicycles is a relatively new trend compared to more traditional road bicycles with tire widths of 19 mm to 23 mm.

[0008] However, when such a wider tire is mounted to a bicycle rim (as shown in FIG. 1), the tire tends to extend ( "bulge") outward relative to the outer width of the rim (denoted as W). This "bulbous" shape of the mounted tire causes aerodynamic and handling problems. First, since the width T of the tire is substantially greater than the outer width W of the rim, this results in an increase in air resistance, which negates any improvement in rolling resistance obtained by using the wider tire. Second, the "bulging" of the tire relative to the rim may cause lateral movement of the tire during use, especially during turning, resulting in adverse handling performance.

[0009] To overcome these problems, bicycle rim manufacturers have started manufacturing "wider" rims, where in response to the more commonly used wider tire width T, the outer rim width W is increased. However, a further consideration that must be taken into account when manufacturing the rim is the inner width ("I") of the rim, which is the distance between a first wall section 11 and a second wall section 12 of the tire mounting portion 10 of the rim.

[0010] The inner width of the rim defines the tire shape by "squeezing" the tire beads together during mounting. Thus, generally, in order to obtain the desired situation where the width T of the inflated tire does not bulge substantially outward from the rim (the desired situation for aerodynamic efficiency is that the width of the mounted tire is approximately equal to or less than the outer width of the rim), it is desirable to increase the difference between the outer width W and the inner width I of the rim compared to a conventional rim shape.

[0011] However, this necessarily requires thicker wall sections of the rim, especially in the tire mounting portion of the rim. When manufacturing the rim, thicker wall sections require an increased amount of material, resulting in a heavier rim. A heavier rim is particularly undesirable due to the increase in the inertia of the rotational movement of the final bicycle wheel, which can lead to slow acceleration and decreased performance. SUMMARY OF THE INVENTION

[0012] According to a first aspect of the present invention, there is provided a rim assembly for a bicycle wheel, the rim assembly comprising: a rim configured to receive a rim member in an outer surface of the rim; and a rim member located in the outer surface of the rim, wherein the rim member forms a part of the outer surface of the rim, and wherein the rim member has a lower density compared to the rim.

[0013] The inventors have recognized that by providing a rim assembly including a rim and a rim member, wherein the rim member has a lower density compared to the rim, the entire rim assembly will be lighter compared to a situation where the rim is not configured to receive such a rim member. This has particular benefits when manufacturing wider rims, as mentioned above, since wider rims require thicker wall sections due to the internal rim width considerations. The rim assembly according to the first aspect of the present invention allows for the manufacture of wider rims with a minimal weight penalty, while having the associated aerodynamic and handling advantages.

[0014] The rim assembly is preferably a one-piece member, by which is meant that the rim and the rim member are integrally connected. Multiple spokes can be used to attach the rim assembly to a hub to form a wheel for a bicycle.

[0015] The rim assembly according to the present invention is particularly suitable for use with a wheel having a disc brake, since the material of the rim member can typically be located in the position of the conventional braking surface for a rim brake. Thus, preferably, the rim member does not form part of the braking section of the rim assembly. In other words, the rim member is preferably used such that the shape and weight of the rim assembly can be advantageously manipulated, rather than using a conventional rim brake to improve braking performance.

[0016] Thus, preferably, the rim assembly is configured for use with a wheel having a disc brake. However, the rim member can be located at a position spaced apart from the braking surface for a rim brake, and in such a case, the rim assembly can be used in a wheel for a rim brake.

[0017] The rim member is typically bonded to the rim, but other methods of attaching the rim member to the rim are also contemplated, such as using flanges or friction fit interfaces. In the case of bonding the rim member to the rim to form the rim assembly, this is preferably performed during a molding process.

[0018] In such a rim assembly, the rim member forms a part of the outer surface of the rim. Preferably, the rim member sits “flush” with the outer surface of the rim. Typically, the exposed surface of the rim member forms a part of the outer surface of the rim.

[0019] The rim component can generally be formed of any material having a lower density than the density of the rim. The material of the rim component can have a self - supporting (preferably integral) form when inserted into the outer surface of the rim. Alternatively or additionally, the rim component material (or a part of the rim component material) can have a form that can be molded (“soft”) when inserted into the outer surface of the rim. Such material is preferably curable. For example, the rim can include a recess in the outer surface of the rim, where the moldable material is used to fill the recess such that the exposed surface of the rim component material forms part of the outer surface of the rim. An example of such a moldable material for forming the rim component is (preferably curable) epoxy resin. The epoxy resin can be in the form of an epoxy adhesive or an epoxy filler.

[0020] Preferably, the rim component comprises a foam material. Such a foam material includes a plurality of air - filled voids. Generally, the foam rim component can be made of a variety of thermosetting and thermoplastic polymers, such as polyvinyl chloride (PVC), polyurethane (PU), polystyrene (PS), styrene acrylonitrile (SAN), polyetherimide (PEI), and polymethacrylimide (PMI), such as PMI isotropic rigid foam. The rim component is preferably made of a thermosetting polymer, such as epoxy resin. A particularly preferred material for the rim component is bisphenol A (BPA) type closed - cell foam. Here, the term “comprises” includes “consists only of”. In other words, the rim component can consist essentially of a foam material, such as a closed - cell foam.

[0021] Other materials that can be used for the rim component include, for example, rubber and plastic materials having a lower density than the rim. Generally, the rim component does not include carbon fiber composites.

[0022] The rim component can be referred to as an insertable rim component.

[0023] In a preferred embodiment, the rim includes a recess in the outer surface of the rim, preferably, where the rim component is located in the recess. The rim component preferably fills the recess substantially completely such that the rim component sits “flush” with the outer surface of the rim. The recess can have a geometric shape that is generally triangular, generally trapezoidal, generally rectangular, or generally hemispherical (e.g., approximately semi - circular).

[0024] Generally, the recess has a depth between 0.5 mm and 4 mm, preferably between 2 mm and 4 mm. Here, the “depth” is the dimension extending inward, for example, substantially perpendicular to the median plane of the rim assembly (the median plane of the rim assembly is the plane of the rim assembly that is symmetric about the axis of rotation).

[0025] The recess may have a radial dimension between 1 mm and 25 mm, preferably between 2 mm and 10 mm, and more preferably between 2 mm and 5 mm.

[0026] Typically, the rim may include one or more recesses, wherein rim components are located within each of the one or more recesses, and each rim component forms part of the outer surface of the rim. Each of the one or more recesses may have the features described herein.

[0027] The rim typically may include opposite outer surfaces, each of the opposite outer surfaces including a recess, wherein the recesses are symmetrically arranged (e.g., about a midplane of the rim assembly), and preferably, wherein a rim component is positioned within each recess such that: each rim component forms part of the outer surface of the rim.

[0028] Typically, the rim of such a rim assembly has: an outer width in the range of 20 mm to 50 mm, preferably in the range of 23 mm to 30 mm; and an inner width in the range of 13 mm to 29 mm, preferably in the range of 17 mm to 25 mm. A preferred configuration has an inner width of 23 mm and an outer width of 28 mm. Here, the outer width is measured at the maximum width of the rim. Typically, this is at the tire mounting portion, but depending on the design of the rim shape (e.g., for aerodynamic purposes), this may be located at a position radially different from the tire mounting portion.

[0029] In various embodiments, the rim assembly may further include a layer of protective material (such as a resin, varnish, or paint layer) applied to the outer surface of the rim component.

[0030] The rim may be made of any material, such as a composite material (e.g., a carbon fiber composite) or a metallic material, or a combination of both, but the rim is typically formed of a carbon fiber composite.

[0031] According to a second aspect of the present invention, there is provided a rim for a bicycle wheel, the rim being configured to receive (e.g., insertable) rim components (e.g., materials for forming rim components) within the outer surface of the rim, wherein when the insertable rim components are inserted, they form part of the outer surface of the rim. As is known in the art, the shape of such a rim for a bicycle wheel is generally annular, and the rim typically includes opposite first and second sidewalls, a tire mounting portion, and a spoke mounting portion.

[0032] Such a rim may be configured to form the rim assembly of the first aspect of the present invention. Accordingly, the following description also relates to the rim of the first aspect of the present invention.

[0033] The inventors have recognized that if an insertable rim component is inserted into the outer surface of a rim and if the rim component is made of a material having a lower density than the rim material, the complete rim assembly (i.e., the rim and the insertable rim component) will be lighter than if the rim were not configured to receive such a rim component.

[0034] This has particular benefits when manufacturing wider rims, as described above in the background section, since wider rims require thicker wall sections due to the width of the inner rim. The rim according to the first aspect of the invention allows for the manufacture of wider rims with a minimal weight penalty, while having associated aerodynamic and handling advantages.

[0035] As used herein, the term "outer surface" refers to the surface of the rim that is exposed to the surrounding environment in an isolated state (i.e., where no tire is mounted on the rim). In other words, when the insertable rim component is inserted, at least a portion of the rim component is exposed to the surrounding environment.

[0036] Preferably, the outer surface is an outward-facing surface, such as the outward-facing surface of the sidewall of the rim. In this context, the term "outward" is used to denote the surface of the rim that is exposed to the surrounding environment when a tire is mounted to the rim. This can be the outer surface of the tire mounting portion of the rim. However, the outer surface can be the inward-facing outer surface or the radially-facing outer surface of the rim (e.g., the portion of the tire mounting portion of the rim that is not exposed when a tire is mounted).

[0037] The rim is configured such that when the insertable rim component is inserted, the insertable rim component forms part of the outer surface of the rim. In other words, when the rim component is inserted, the rim component conforms to the outer surface of the rim surrounding the rim component, and preferably the rim component sits flush with the outer surface of the rim surrounding the rim component.

[0038] The rim can be made of any material, such as a composite material or a metallic material, or a combination of both, but is typically made substantially entirely of a carbon fiber composite. Typically, pre-impregnated ("prepreg") carbon fiber sheets - meaning that the carbon fibers have been arranged in a resin matrix such as epoxy resin - are placed in a suitable mold and cured to form the rim. Importantly, the prepreg sheets are bonded together in a reliable manner to establish the strength and integrity of the rim. Since the rim component will not be completely surrounded by the prepreg sheets, configuring the rim to receive the insertable rim component in the outer surface of the rim advantageously means that the bonding of the prepreg sheets to each other can be easily controlled.

[0039] Using the outer surface of the rim to receive the rim component also advantageously provides increased flexibility in the positioning of such a rim component.

[0040] In a preferred embodiment, the rim includes a recess in an outer surface of the rim, the recess being configured to receive an insertable rim component. Generally, the inserted rim component substantially completely fills the recess such that an exposed surface of the rim component forms part of the outer surface of the rim. The recess is provided as a notch in the outer surface of the rim and the recess may be in the form of a "groove" or a "slot".

[0041] Generally, the recess may be located at any position in the outer surface of the rim. In a preferred embodiment, the rim includes generally opposite outer surfaces, at least one of the generally opposite outer surfaces including a recess. Preferably, the rim includes opposite recesses in the opposite outer surfaces to enable the entire rim to rotate "correctly", i.e., with minimal lateral deviation. Preferably, the recess(es) of the rim are symmetric about a midplane of the rim (the midplane of the rim is a plane of the rim that is symmetric perpendicular to the axis of rotation) and symmetric about the axis of rotation.

[0042] Preferably, the rim includes at least one generally annular recess in at least one outer surface of the rim. Particularly preferably, the rim includes generally opposite annular recesses in the opposite outer surfaces. Here, the term "annular recess" is used to describe the shape of the recess when viewed in a direction parallel to the axis of rotation of the rim. Such an annular recess may be described as extending circumferentially. Such an annular recess(es) is beneficial as it can be formed relatively simply while allowing the insertion of relatively large (lower density) rim components. In addition, such an annular recess(es) is rotationally symmetric about the axis of rotation of the rim, thereby ensuring good rotation of the finished wheel.

[0043] However, other recess geometries and positions are conceivable. For example, the rim may include a plurality of discrete recesses in at least one outer surface of the rim. Such a plurality of recesses may be spaced apart radially or circumferentially and preferably exhibit rotational symmetry about the axis of rotation of the rim. In such an embodiment, the plurality of recesses are configured to receive a corresponding plurality of insertable rim components.

[0044] Preferably, the rim includes opposite first and second wall sections, each of the first and second wall sections including an outer surface, and wherein at least one of the first and second wall sections includes a recess in the outer surface of the at least one. Generally, such first and second wall sections are configured for mounting a bicycle tire. It is particularly advantageous to locate a plurality of recesses in the wall sections configured for mounting a bicycle tire as these wall sections will typically be the thickest part of the rim (and thus require the most material) due to the requirements of the internal rim width and secure mounting of the tire.

[0045] (When viewed in a direction perpendicular to the axis of rotation of the rim), the recess(es) can generally have any cross-sectional geometry. However, preferably, the recess(es) are configured to receive insertable rim components having a cross-sectional geometry that is generally triangular, generally trapezoidal, generally rectangular, or generally hemispherical (e.g., approximately semi-circular).

[0046] The insertable rim component that can be inserted into the outer surface of the rim can generally be formed of any material having a lower density than the density of the rim. The material of the insertable rim component can have a form that is self-supporting (preferably integral) when inserted into the outer surface of the rim. Alternatively or additionally, the rim component material (or a portion of the rim component material) can have a form that is capable of being molded ("soft") when inserted into the outer surface of the rim. Such a material is preferably curable. For example, the rim can include a recess in the outer surface of the rim, wherein a moldable material is used to fill the recess such that the exposed surface of the rim component material forms part of the outer surface of the rim. An example of such a moldable material is (preferably curable) epoxy resin. The epoxy resin can be in the form of an epoxy adhesive or an epoxy filler.

[0047] The insertable rim component material can then be cured (e.g., together with the rim) within the rim by applying heat to undergo cross-linking and hardening.

[0048] A particularly preferred material for the rim component is a bisphenol A (BPA)-type closed-cell foam.

[0049] According to a third aspect of the present invention, there is provided a method of manufacturing a rim assembly for a bicycle wheel, the method comprising: providing a rim configured to receive a rim component in the outer surface of the rim; and inserting a material for forming the rim component into the outer surface of the rim such that the inserted material for forming the rim component forms part of the outer surface of the rim, wherein the material for forming the rim component has a lower density than the rim.

[0050] The rim component material can have a form that is self-supporting (preferably integral) when inserted into the outer surface of the rim. Alternatively or additionally, the rim component material (or a portion of the rim component material) can have a form that is capable of being molded ("soft") when inserted into the outer surface of the rim. Such a material is preferably curable. For example, the rim can include a recess in the outer surface of the rim, wherein a moldable rim component material is used to fill the recess such that the exposed surface of the rim component material forms part of the outer surface of the rim.

[0051] Preferably, the method further comprises curing, preferably by applying heat, the material for forming the rim part within the rim (e.g., together with the rim). This is typically carried out in a mold that defines the desired outer surface of the rim assembly. Thus, preferably, the material for forming the rim part is a curable material, such as a curable polymer. An example of such a material for forming the rim part is an epoxy resin, which can be in the form of an epoxy adhesive or an epoxy resin. The material forms a foam structure upon curing, such that the formed rim part comprises a foam material. The rim part can consist only of the foam material (e.g., consist essentially of the foam material). A particularly preferred material for the rim part is a BPA-type closed-cell foam.

[0052] Preferably, the rim includes recesses on the outer surface of the rim. Preferably, the material for forming the rim part is inserted into the recesses such that the recesses are substantially completely filled with the material for forming the rim part. The rim can be formed by conventional methods, such as closed-mold processing or fiber winding. In a preferred embodiment, the step of providing the rim comprises assembling (e.g., arranging) the rim material in a mold for forming the rim and preferably curing the rim material within the mold, the rim including recesses in the outer surface of the rim. Such a mold will typically have protrusions (e.g., ridges) corresponding to the recesses to be formed in the outer surface of the rim.

[0053] Preferably, the rim material is a composite material, preferably a carbon fiber composite.

[0054] In some embodiments, a protective material layer (e.g., a resin, varnish, or paint layer) can be applied to the outer surface of the material for forming the rim part to protect it from damage.

[0055] The method of the third aspect of the present invention can be adapted to manufacture a rim assembly according to the first aspect of the present invention. Generally, the provided rim is a rim according to the second aspect of the present invention. Thus, the provided rim can have any of the features discussed above with respect to the first and second aspects of the present invention.

[0056] According to a fourth aspect of the present invention, there is provided a bicycle wheel comprising a rim or a rim assembly according to the present invention.

[0057] According to a fifth aspect of the present invention, there is provided a mold for a bicycle rim, the mold being adapted to provide a rim and / or a rim assembly according to the present invention.

[0058] According to a sixth aspect of the present invention, there is provided an insertable rim component for a bicycle wheel rim, the rim component being configured to be insertable into an outer surface of a rim for a bicycle wheel such that the rim component forms part of the outer surface of the rim when inserted, and wherein the rim component has a lower density than the rim. As described above, using such an insertable rim component having a lower density than the rim advantageously allows the width of the rim to be increased with a minimal weight penalty.

[0059] Preferably, the insertable rim component is configured to cooperate with a recess located in the outer surface of a rim for a bicycle wheel.

[0060] The insertable rim component can generally have any cross-sectional geometry. However, preferably, the insertable rim component has a cross-sectional geometry that is generally triangular, generally trapezoidal, generally rectangular, or generally hemispherical. As described above, a preferred recess configuration for the rim is that the recess is generally annular. In this case, the insertable rim component is preferably generally annular and adapted to cooperate with the annular recess of the rim. The insertable rim component can be self-supporting.

[0061] The insertable rim component has a lower density than the rim and can generally be formed from any material that exhibits this property. Preferably, the insertable rim component comprises a foam material. Generally, the foam insertable rim component can be manufactured from a variety of thermosetting and thermoplastic polymers such as: polyvinyl chloride (PVC), polyurethane (PU), polystyrene (PS), styrene acrylonitrile (SAN), polyetherimide (PEI), and polymethacrylimide (PMI), such as PMI isotropic rigid foam. Preferably, the insertable rim component is a BPA-free closed-cell foam.

[0062] There is also disclosed herein a rim assembly for a bicycle wheel, the rim assembly comprising: a rim according to a second aspect of the present invention; and a rim component located in an outer surface of the rim, wherein the rim component forms part of the outer surface of the rim, and wherein the rim component has a lower density than the rim.

[0063] Such a rim assembly is particularly suitable for use with wheels for disc brakes, since the material of the rim component can generally be located in the position of the conventional braking surface where the rim brake will be located. However, the rim component can be located at a position spaced apart from the braking surface for the rim brake, and in this case, the rim assembly can be used in a wheel for a rim brake.

[0064] Rim components are typically bonded to the rim, but other methods of attaching the rim component to the rim can also be envisaged, such as using flanges or friction fit interfaces. In the case where the rim component is bonded to the rim to form a rim assembly, this is preferably carried out during the molding process of the rim. For example, sheets of carbon fiber prepreg can be assembled in a mold to form a rim with a recess in its outer surface. The rim component can then be positioned within the recess within the mold and bonded to the sheet of prepreg within the mold during the molding process. This can be carried out during the curing process. In other embodiments, the rim component can be bonded to the rim after the molding process.

[0065] In such a rim assembly, the exposed surface of the rim component forms part of the outer surface of the rim. Preferably, the rim component sits "flush" with the outer surface of the rim.

[0066] The rim component material can have a form that is self - supporting (preferably integral) when inserted into the outer surface of the rim. Alternatively or additionally, the rim component material (or a part of the rim component material) can have a form that is capable of being molded ("soft") when inserted into the outer surface of the rim. An example of such a moldable material is (preferably curable) epoxy resin. The epoxy resin can be in the form of an epoxy adhesive or an epoxy filler.

[0067] The rim component can be an insertable rim component according to the sixth aspect of the present invention.

[0068] Typically, the rim of such a rim assembly has an outer width in the range of 20 mm to 50 mm and an inner width in the range of 13 mm to 29 mm. A preferred configuration has an inner width of 23 mm and an outer width of 28 mm. Here, the outer width is measured at the maximum width of the rim. Typically, this is at the tire mounting portion, but depending on the design of the rim shape (e.g., for aerodynamic purposes), this can be located at a position radially different from the tire mounting portion.

[0069] Also disclosed herein is a method of manufacturing a rim assembly for a bicycle wheel, the method comprising: providing a rim according to the second aspect; and inserting a rim component (e.g., the material for forming the rim component) into the outer surface of the rim such that the inserted rim component (e.g., the material for forming the rim component) forms part of the outer surface of the rim, wherein the rim component has a lower density than the rim. The rim component can be an insertable rim component according to the second aspect of the present invention. The rim can be formed by conventional methods such as closed - mold processing or fiber winding.

[0070] The rim component material can have a self - supporting (preferably integral) form when inserted into the outer surface of the rim. Alternatively or additionally, the rim component material (or a part of the rim component material) can have a form that can be molded ("soft") when inserted into the outer surface of the rim. Such material is preferably curable. For example, the rim can include recesses in its outer surface, where the moldable rim component material is used to fill the recesses such that the exposed surface of the rim component material forms part of the outer surface of the rim. Then the rim component material can be cured within the rim (e.g., together with the rim) by applying heat.

[0071] Also disclosed herein is a method of manufacturing a rim assembly for a bicycle wheel, the method comprising: assembling rim material in a mold shaped for a rim according to the second aspect; disposing a rim component (e.g., material for forming the rim component) within the outer surface of the rim material within the mold such that the rim component forms part of the outer surface of the rim; and curing the rim material and the rim component (e.g., material for forming the rim component) within the mold such that the rim component binds to the rim material within the mold. This method of manufacturing a rim assembly is particularly advantageous because the rim component is formed integrally with the rim during the molding process.

[0072] The rim component material can have a self - supporting form. Alternatively or additionally, the rim component material (or a part of the rim component material) can have a moldable ("soft") form, such as epoxy resin.

[0073] Preferably, the rim material is a composite material, preferably a carbon fiber composite. In this method, sheets of carbon fiber prepreg are typically assembled in the mold together with the rim component, where during the molding process, the rim component binds to the sheets of prepreg within the mold.

[0074] In an alternative embodiment, it is contemplated that the rim material can be disposed within the mold around (preferably self - supporting) the rim component such that the rim component forms part of the outer surface of the rim.

[0075] Also disclosed herein is a rim assembly for a bicycle wheel, the rim assembly including a rim body formed of a first material and a rim component located in the outer surface of the rim body, wherein the rim component forms a part of the outer surface of the rim body, and wherein the rim component is formed of a second material having a lower density than the first material. The material of the rim component may have a self-supporting form when inserted into the outer surface of the rim body. The material of the rim component may have a form that is capable of being molded ("soft") when inserted into the outer surface of the rim body. Such a material is preferably curable. For example, the rim body may include a recess in the outer surface of the rim body, wherein a moldable material is used to fill the recess such that the exposed surface of the rim component material forms a part of the outer surface of the rim body. An example of such a moldable material is (preferably curable) epoxy resin. The epoxy resin may be in the form of an epoxy adhesive or an epoxy filler.

[0076] Also disclosed herein is a method of manufacturing a rim assembly for a bicycle wheel, the method comprising: providing a rim that includes a recess in the outer surface of the rim; using an insert material to substantially completely fill the recess of the rim such that the insert material forms a part of the surface of the rim, the insert material having a lower density than the rim, and preferably curing the insert material within the rim to form the rim assembly.

[0077] The insert material may have a moldable ("soft") form (examples include epoxy resins such as epoxy adhesives or epoxy fillers). Alternatively or additionally, the insert material (or a part of the insert material) may have a self-supporting form. The curing is preferably thermal curing.

[0078] In some embodiments, a protective material layer (such as a resin, varnish, or paint layer) may be applied to the outer surface of the insert material of the rim assembly to protect it from damage.

[0079] The material of the (insertable) rim component in any of the above aspects has a lower density than the rim and may generally be formed of any material that exhibits this property. The material may include foam materials. Generally, foam rim components may be made of a variety of thermosetting and thermoplastic polymers such as: polyvinyl chloride (PVC), polyurethane (PU), polystyrene (PS), styrene acrylonitrile (SAN), polyetherimide (PEI), and polymethacrylimide (PMI), such as PMI isotropic rigid foam. Other examples of materials that may be used to form the rim component according to the present invention include (preferably curable) epoxy resins, such as epoxy adhesives or epoxy fillers. Description of the Drawings

[0080] The present invention will now be described in conjunction with the accompanying drawings, in which:

[0081] FIG. 1 schematically shows a bicycle tire mounted to a conventional rim;

[0082] Figure 2 is a schematic side view of a bicycle wheel including a rim assembly according to an embodiment of the present invention;

[0083] Figure 3 is a perspective view of a part of the rim assembly according to the present invention;

[0084] Figure 4 is a perspective view of a part of the rim according to the present invention;

[0085] Figure 5 is a cross-sectional view of the rim assembly according to the present invention;

[0086] Figure 6 is a cross-sectional view of the rim according to the present invention;

[0087] Figure 7 schematically shows a bicycle tire mounted to the rim assembly according to the present invention;

[0088] Figure 8 shows an exemplary insertable rim component according to the present invention;

[0089] Figures 9 to 13 schematically shows the geometry of an exemplary recess and an insertable rim component that can be used in the present invention;

[0090] Figure 14 shows a cross-section of a hookless rim;

[0091] Figure 15 shows a cross-section of a rim adapted to mount a tubular tire; and

[0092] Figure 16 is a flowchart outlining the steps of a preferred method for forming a rim assembly according to the present invention. DETAILED DESCRIPTION

[0093] Figure 2 is a schematic side view of a bicycle wheel 1000 including a rim assembly 100, the rim assembly being a rim assembly according to an embodiment of the present invention. The rim assembly 100 includes a rim 100a and an insertable rim component 50a, the rim component 50a being located in the outer surface of the rim 100 such that the rim component 50a forms part of the outer surface of the rim. For ease of description, in the remainder of the specification, the insertable rim component may simply be referred to as an "insert".

[0094] The wheel 1000 is shown without a tire mounted thereon. As can be seen, the shape of the rim 100a is generally annular and has a depth "D" which is the distance between the radially inner part and the radially outer part of the rim. A tire (which may be a tubeless tire, a tubular tire or a clincher tire) is mounted to the radially outer tire mounting portion 10 of the rim.

[0095] The wheel also includes a hub 300 and a plurality (usually between 16 and 36) of spokes 400 that connect the hub to the rim. Each spoke is attached to a spoke engagement portion 7 located at the radially inner part of the rim. Each spoke typically includes a threaded section and is attached to the spoke engagement portion 7 by using a spoke cap 410. The wheel 1000 has a rotational axis that extends into the plane of the paper through the center of the hub 300.

[0096] In this example, the wheel 1000 includes a disc brake rotor 500 mounted on the hub 300. When the wheel is mounted to a bicycle frame, a brake caliper attached to the bicycle frame can engage with the rotor to decelerate the bicycle.

[0097] The rim 100a includes a first sidewall 5. A generally annular recess 20a (see Figure 4 ) is formed in the outward-facing outer surface of the sidewall 5, and the recess extends circumferentially around the rim with a radius R, as seen in Figure 2 . The radial dimension ("width") x of the recess 20a is between 1 mm and 25 mm, preferably between 2 mm and 10 mm, more preferably between 2 mm and 5 mm, and most preferably 3.4 mm. A corresponding recess is formed in the outward-facing outer surface of the opposite sidewall 3 of the rim 100a.

[0098] The recess 20a is substantially filled with an insert 50a (see Figure 3 ), such that the exposed (outer) surface of the insert 50a substantially conforms to the outer surface of the sidewall 5 of the rim 100a. The insert 50a has a lower density relative to the material forming the rim 100a, and thus, the entire rim assembly 100 advantageously has a reduced weight compared to the case where there are no recesses and inserts.

[0099] The rim 100a can be formed of any material. For example, a composite material (such as a carbon fiber composite), a metal alloy (such as an aluminum alloy), and / or any other material can be used. A combination of materials can be used, for example, a part of the rim 100a can be formed of a carbon fiber composite and a part can be formed of aluminum. In this particular embodiment, the rim 100a is a one-piece member formed of a carbon fiber composite.

[0100] The insert is typically a foam material including a plurality of air-filled voids, and in this embodiment the insert is a polymethacrylimide (PMI) isotropic rigid foam with a density of 0.4 g / cm 3 , having high strength, modulus and heat resistance. Other suitable low-density insert materials can be used, and such low-density insert materials include honeycomb structures. The insert material is typically bonded to the rim 100a to form a complete rim assembly 100, but other ways of coupling the insert material to the rim can also be envisioned, such as a flange member circumferentially positioned around the recess 20a, or a friction fit between the rim 100a and the insert.

[0101] The insert can be formed of any material having a density lower than that of the rim. The insert can be provided as a one-piece member shaped to cooperate with the corresponding recess. Alternatively or additionally, the material used to form the insert can have a form that is moldable ("soft") when used to fill the recess 20a. An example of such a moldable material is epoxy resin.

[0102] Figure 5 is a cross-sectional view through the rim assembly 100, showing the rim 100a and the inserts 50a and 50b. As described above, Figure 2 the sidewall 3 opposite the sidewall 5 as visible in Figure 6 includes corresponding recesses 20b in its outer surface facing the outside (see

[0103] ). The recesses 20a, 20b are symmetrically positioned about the middle plane (P) of the rim, which is a plane perpendicular to the axis of rotation and bisecting the rim. This ensures the correct balance of the rim assembly 100 in the presence of the inserts. Figure 5 and Figure 6 as can be seen in Figure 6 which shows the rim 100a without the insert material), the recesses 20a, 20b are configured to receive inserts 50a, 50b having a generally trapezoidal cross-section. In other words, when viewed in cross-section as in Figure 5 and Figure 6 , each recess 20a, 20b includes two generally inwardly extending surfaces (shown as 21a, 21b) and one generally radially extending surface 22. However, other recess cross-sectional geometries can be envisioned, as shown in Figure 9 and Figure 10 .

[0104] As Figure 5As can be seen, the inserts 50a, 50b substantially completely fill the respective recesses 20a, 20b such that when the inserts are coupled to the rim 100a, the exposed outer surfaces of the inserts (shown as 51a, 51b) generally conform to the outer surface of the rim. In this embodiment, the inserts are seated "flush" with the outer surface of the rim 100a.

[0105] In the presently described embodiment, the recesses 20a, 20b are located in the wall sections 11, 12 of the tire mounting portion 10 of the rim. For the purposes of the present disclosure, these first wall section 11 and second wall section 12 form part of the first and second sidewalls of the rim. Due to the limitations on the internal width I of the rim discussed in the background of the present invention, it has been found that the recesses have particular benefits when located in these wall sections. Using inserts having a density lower than that of the rim 100a advantageously allows the outer width W of the rim to be increased with a minimal weight penalty. The typical width z of the wall sections 11, 12 (see Figure 6 ) is in the range of 1 mm to 5 mm. The recesses generally have a depth (i.e., the dimension extending inwardly) greater than 0.5 mm and less than 4 mm, preferably between 2 mm and 4 mm.

[0106] Figure 7 Schematically shown is a tire 200 mounted to a rim assembly 100 according to the presently described embodiment of the present invention. In this embodiment, the rim 100 is adapted for the attachment of an open - tire type tire, as Figure 7 shown, and there is also an inner tube 210 in Figure 7 . However, it should be understood that the rim can be adapted for the assembly of other tire mounting configurations, such as tubeless and tube - type tires. As can be seen from Figure 7 , compared to FIG. 1, the width T of the mounted tire is more closely aligned with the maximum outer width W of the rim 100. The use of a wider rim in this case allows for improved aerodynamic and handling characteristics as described above, while the use of the inserts 50a, 50b within the respective recesses 20a, 20b in the rim 100a allows the outer width of the rim (constrained by the internal width I) to be increased with a minimal weight penalty.

[0107] The typical internal width I of the rim that can be used in the present invention is in the range of 13 mm to 29 mm, and the outer width of the rim (measured at the maximum outer width) is generally in the range of 20 mm to 50 mm. In a particularly preferred configuration, the internal width I is 19 mm and the outer width W is 27 mm. The depth D of the rim is generally between 10 mm and 80 mm, preferably between 30 mm and 60 mm.

[0108] As can be seen from Figure 7As can be seen, in this embodiment, compared to the tire mounting portion, the maximum outer width W of the rim is located at a radially inner section of the rim. However, compared to a conventional rim, the width of the rim at the tire mounting portion is also increased. In other embodiments, the maximum outer width of the rim can be at the tire mounting portion or at other radial positions of the rim between the tire mounting portion and the spoke engagement portion.

[0109] In this embodiment, as explained with respect to Figure 2 Since the inserts 50a, 50b are located at the positions where the braking surfaces of a conventional rim brake rim are typically located, the rim assembly 100 is designed to be used on a disc brake wheel. However, it is conceivable that in other embodiments, the recess(es) and corresponding insert(s) in the rim 100a can be located at positions spaced apart from the braking track, and such a rim can be used with a rim brake caliper.

[0110] The rim 100a is preferably made entirely of a carbon fiber composite material. Pre-impregnated ("prepreg") carbon fiber sheets - meaning that the carbon fibers are already arranged in a resin matrix such as epoxy resin - can be placed in a suitable mold and cured to form the rim 100a. In one embodiment, after removing the insert material from the mold, the insert material is subsequently bonded to the rim 100a. In Figures 2 to 7 In the exemplary rim 100 as seen in Figure 8 the insert can be formed as a generally annular one-piece member as seen in

[0111] which has the geometry required to fit into the recesses 20a, 20b in the rim 100a and substantially completely fills the recesses 20a, 20b in the rim 100a.

[0112] In an alternative method, the insert(s) can be placed in a mold with a carbon fiber laminate such that the insert material is bonded to the rim 100a within the mold and during the molding process.

[0112] In any of the examples discussed herein, the insertable rim component ("insert material") can be formed from a material that has a soft molding form when inserted into the recess(es) of the rim. In this case, it is preferred to cure the insert material within the rim (e.g., together with the rim) to form the rim assembly.

[0113] In the exemplary rim 100 described so far, the recesses 20a, 20b are configured to receive corresponding inserts having a generally trapezoidal cross-sectional geometry. However, other cross-sectional geometries of the recesses and corresponding inserts are conceivable, as seen in Figure 9 and Figure 10 as seen in. Figure 9illustrates the following exemplary rim assembly 110: The rim assembly 110 includes a rim 110a having recesses 20a, 20b configured to receive inserts having a geometry with a generally triangular cross-section, and Figure 10 illustrates the following exemplary rim assembly 120: The rim assembly 120 has recesses 20a, 20b in a rim 120a of the rim assembly 120, the recesses 20a, 20b being configured to receive inserts having a generally hemispherical cross-section geometry.

[0114] Figure 11 illustrates an exemplary rim assembly 130 in which recesses 20a, 20b are formed in an inward-facing outer surface of a rim 130a. More specifically, in this example, the recesses 20a, 20b and associated inserts are located on the inward-facing outer surfaces of wall sections 11, 12.

[0115] Figure 12 illustrates an exemplary rim assembly 140 that includes a single recess 20 in a radially outward-facing surface of a tire mounting portion 10. The recess 20 extends circumferentially around the rim and is symmetric about a midplane P of the rim. Such a recess, as seen in Figure 12 allows for a wider bicycle wheel rim with a reduced weight while still having less material required to form the rim 140 compared to a situation where there are no recesses and inserts.

[0116] Figure 13 shows a side view of a bicycle rim assembly 150 according to another embodiment of the present invention, in which the outer surface of the rim 150a includes a plurality of discrete recesses 20 spaced circumferentially around the rim. The recesses and associated inserts 50 are preferably positioned symmetrically about the circumference of the rim such that the rim assembly exhibits rotational symmetry about the axis of rotation of the rim assembly.

[0117] So far, embodiments have been described with respect to rims configured for a clincher tire configuration or a tubeless tire configuration, where wall sections 11, 12 of a tire mounting portion 10 of the rim include inward-facing hook portions 11a, 12a. In other embodiments, the rim can be "hookless", in which case the wall sections 11, 12 do not include inwardly extending hook portions. This is shown in the rim assembly 160 as shown in Figure 14 In another embodiment, the rim assembly 170 can be configured for mounting a tubular tire, where the tire is glued or bonded to a radially outer tire mounting portion of the rim 170a, as shown in

[0118] Figure 15As schematically shown. Although such a rim configured for a tubular tire does not include wall sections 11, 12 at the tire mounting portion, the rim 170a includes recesses 20a, 20b in the outward-facing outer surface and corresponding inserts 50a, 50b to advantageously reduce weight.

[0119] A preferred method for manufacturing a rim assembly for a bicycle wheel will now be described. In a first step, a rim is provided that has recesses (e.g., as shown in Figure 4 as shown) in the outward-facing outer surface of the sidewall. The rim can be manufactured using standard procedures. An example of manufacturing such a rim is by hand-laying pre-impregnated carbon fiber sheets on a preform mold that has ridges corresponding to the recesses to be formed within the rim. The rim is then cured within the mold.

[0120] In a second step, a curable and moldable insert material (usually an epoxy resin) is typically inserted into the recesses of the rim so that the curable and moldable insert material substantially completely fills the recesses. In other words, the curable material sits "flush" with the outer surface of the rim.

[0121] In a third step, the rim and the insert material are placed into a second mold that defines the desired outer surface of the rim assembly. The rim and the insert material are then cured together within the second mold by applying heat (usually in the range of 100°C to 200°C, preferably 120°C to 150°C).

[0122] As described above with reference to the drawings, the rim provided in the first step can have one or more recesses, and the one or more recesses can have various different geometries and positions on the rim.

[0123] Figure 16 is a flow chart that outlines the steps of the preferred method for manufacturing the rim assembly described above. The first step of providing the rim that has recesses in the outward-facing surface of the sidewall is shown as step S101. Step S102 shows the second step of typically inserting a curable and moldable insert material into the recesses of the rim to completely fill the recesses. The third step of placing the rim and the insert material into a second mold that defines the outer surface of the rim assembly is shown as step S103. The step of curing the rim and the insert material together within the second mold is shown as step S104.

Claims

1. A rim assembly for a bicycle wheel, the rim assembly comprising: a rim having a tire mounting portion, the rim including opposite first and second wall sections, wherein at least one of the first and second wall sections has a recess configured to receive a rim component; and a rim component located within the recess, and wherein, the rim component has a lower density than the rim.

2. The rim assembly according to claim 1, wherein, The rim component comprises a foam material.

3. The rim assembly according to claim 2, wherein, The foam material is a closed-cell foam material.

4. The rim assembly according to any one of claims 1 to 3, wherein, The rim component does not form part of the braking section of the rim assembly.

5. The rim assembly according to any one of claims 1 to 3, wherein, The recess is located in the outer surface of the first wall section and / or the outer surface of the second wall section.

6. The rim assembly according to any one of claims 1 to 3, wherein, The recess is substantially annular.

7. The rim assembly according to any one of claims 1 to 3, wherein, The recess is located in the outward-facing outer surface of the first wall section and / or the outward-facing outer surface of the second wall section.

8. The rim assembly according to any one of claims 1 to 3, wherein, Each of the first and second wall sections includes the recess, and wherein a rim component is positioned within each recess.

9. The rim assembly according to any one of claims 1 to 3, wherein, The first and second wall sections are configured for mounting a bicycle tire.

10. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a cross-sectional geometry that is substantially triangular, substantially trapezoidal, substantially rectangular, or substantially hemispherical.

11. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a depth between 0.5 mm and 4 mm.

12. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a depth between 2 mm and 4 mm.

13. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a radial dimension between 1 mm and 25 mm.

14. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a radial dimension between 2 mm and 10 mm.

15. The rim assembly according to any one of claims 1 to 3, wherein, The recess has a radial dimension between 2 mm and 5 mm.

16. The rim assembly according to any one of claims 1 to 3, wherein, The rim component does not include a carbon fiber composite.

17. The rim assembly according to any one of claims 1 to 3, wherein, The rim component is bonded to the rim.

18. The rim assembly according to any one of claims 1 to 3, wherein, The rim assembly is a one-piece member.

19. The rim assembly according to any one of claims 1 to 3, wherein, The rim assembly is configured for a wheel to be used with a disc brake.

20. The rim assembly according to any one of claims 1 to 3, wherein, The rim assembly further includes a protective material layer applied to the outer surface of the rim component.

21. The rim assembly according to any one of claims 1 to 3, wherein, The rim has an outer width in the range of 20 mm to 50 mm; and the rim has an inner width in the range of 13 mm to 29 mm.

22. The rim assembly according to any one of claims 1 to 3, wherein, The rim has an outer width in the range of 23 mm to 30 mm; and the rim has an inner width in the range of 13 mm to 29 mm.

23. The rim assembly according to any one of claims 1 to 3, wherein, The rim has an outer width in the range of 20 mm to 50 mm; and the rim has an inner width in the range of 17 mm to 25 mm.

24. The rim assembly according to any one of claims 1 to 3, wherein, The rim has an outer width in the range of 23 mm to 30 mm; and the rim has an inner width in the range of 17 mm to 25 mm.

25. The rim assembly according to any one of claims 1 to 3, wherein, The rim is formed of a carbon fiber composite.

26. A method of manufacturing a rim assembly for a bicycle wheel, the method comprising: disposing rim material in a mold shaped for the rim such that the rim has a tire mounting portion, and the rim includes opposite first and second wall sections, wherein at least one of the first and second wall sections has a recess; Arrange the material for forming the rim component in the recess such that the material for forming the rim component conforms to the outer surface of the rim material surrounding the rim component, wherein the material for forming the rim component has a lower density than the rim material; And Cure the rim material and the material for forming the rim component in the mold such that the rim component is bonded to the rim material within the mold.

27. The method according to claim 26, wherein The rim material is a composite material.

28. The method according to claim 26, wherein The rim material is a carbon fiber composite.

29. The method according to any one of claims 26 to 28, wherein, The material for forming the rim component has a form that can be molded when inserted into the outer surface of the rim.

30. The method according to any one of claims 26 to 28, wherein The material for forming the rim component has a self - supporting form when inserted into the outer surface of the rim.

31. The method according to any one of claims 26 to 28, wherein The material for forming the rim component is epoxy resin.

32. The method according to any one of claims 26 to 28, wherein, The method further includes applying a protective material layer to the outer surface of the material for forming the rim component.

33. The method according to any one of claims 26 to 28, wherein, The method is suitable for manufacturing a rim assembly according to any one of claims 1 to 25.

34. A rim assembly manufactured by a method according to any one of claims 26 to 33.

35. A bicycle wheel, wherein, The bicycle wheel includes a rim assembly according to any one of claims 1 to 25 or the rim assembly according to claim 34.

36. A mold for a bicycle rim, wherein, The mold is suitable for providing a rim assembly manufactured by a method according to any one of claims 26 to 33.

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