RIM FIBRE ARCHITECTURE OF A COMPOSITE WHEEL

Abstract

A rim portion of a composite wheel comprises a shaped annulus formed about a central axis of rotation of the composite wheel and having a circumferential axis extending circumferentially about the central axis and around the rim portion, said rim portion having a fibre layup comprising a stacked laminate formed from alternating layers of: a hoop tow layer comprising elongate fibre tow in which the fibres are substantially aligned with the circumferential axis of the rim portion, the hoop tow layer being formed from at least one annularly wound elongate fibre tow; and a bias ply layer comprising at least one fibre ply in which the fibres are substantially orientated at an angle of + or to the circumferential axis of the rim portion, wherein is from 26 to 40.

Claims

1. A rim portion of a composite wheel of a vehicle, the rim portion comprising a shaped annulus formed about a central axis of rotation of the composite wheel and having a circumferential axis extending circumferentially about the central axis and around the rim portion, said rim portion having a fibre layup comprising a stacked laminate formed from alternating layers of: a hoop tow layer comprising elongate fibre tow in which the fibres are substantially aligned with the circumferential axis of the rim portion, the hoop tow layer being formed from at least one annularly wound elongate fibre tow; and a bias ply layer comprising at least one fibre ply in which the fibres are substantially orientated at an angle of + or to the circumferential axis of the rim portion, wherein is from 26 to 40.

2. A rim portion of a composite wheel according to claim 1, wherein is from 28 to 40, preferably 30 to 36, and more preferably about 33.

3. A rim portion of a composite wheel according to claim 1, wherein the hoop tow layer comprises between 40 to 60%, preferably about 50% of fibre in the rim portion.

4. A rim portion of a composite wheel according to claim 1, wherein the bias ply layer comprises between 40 to 60%, preferably about 50% of the fibre in the rim portion.

5. A rim portion of a composite wheel according to claim 1, wherein consecutive bias ply layers are arranged in the lay up to provide a layer having a fibre orientation angle that is the (+ or ) alternate angle of the fibre orientation of the preceding bias ply layer.

6. A rim portion of a composite wheel according to claim 1, wherein the bias plies comprise a sheet of interconnected unidirectional fibre material, preferably a stitched unidirectional sheet material, preferably a stitched unidirectional tow sheet.

7. (canceled)

8. A rim portion of a composite wheel according to claim 1, wherein bias ply comprises a two layer bias ply comprising a layer having fibre directions of +(26 to 40) and a layer having fibre directions of (26 to 40).

9. A rim portion of a composite wheel according to claim 1, wherein the rim portion includes two annular flanges, an inner flange and an outer flange, at opposing edges of the width of the rim portion and each bias ply comprises a continuous sheet from the inner flange of the wheel to the outer flange of the wheel.

10. A rim portion of a composite wheel according to claim 1, wherein each bias ply layer is sandwiched between adjacent hoop tow layers.

11. A rim portion of a composite wheel according to claim 1, wherein each bias ply layer is formed without butt joins.

12. A rim portion of a composite wheel according to claim 1, wherein the stacked laminate further comprises contoured features formed from aggregated hoop wound tow, the contoured features extending around the circumference of the rim portion and are built up from annularly wound elongate fibre tow, and wherein the contoured features include at least one bead, flange, rib, or step.

13.-14. (canceled)

15. A rim portion of a composite wheel according to claim 1, wherein the rim portion includes a drop center recess comprising an annular section having reduced or less tow than sections adjacent to the drop center recess.

16. A rim portion of a composite wheel according to claim 15, further comprising at least one reinforcement layer located in the drop center recess, said reinforcement layer comprising a fibre ply having fibres orientated from 80 to 100 degrees to the circumferential axis of the rim portion, preferably about 90 degree to the circumferential axis of the rim portion, wherein at least one hoop tow layer is provided over at least the ends of the reinforcement layer.

17. (canceled)

18. A rim portion of a composite wheel according to claim 1, wherein radially extending or aligned sections of the rim portion (relative to the central axis) comprise reduced or less tow than sections adjacent thereto.

19. A rim portion of a composite wheel according to claim 1, wherein the rim portion includes two annular flanges, an inner flange and an outer flange, at opposing edges of the width of the rim portion, and wherein the layup of at least one of the inner flange or outer flange includes a reinforcement layer comprising a fibre ply having fibres orientated from 80 to 100 degrees to the circumferential axis of the rim portion, preferably about 90 degree to the circumferential axis of the rim portion.

20. A rim portion of a composite wheel according to claim 1, wherein the fibre density in each layer of the stacked laminate is from 50 to 400 g/m2, preferably from 180 to 250 g/m2, more preferably from 180 to 220 g/m2, yet more preferably about 200 g/m2.

21. A rim portion of a composite wheel according to claim 1, further including a close out ply layer on at least one outer side of the laminated layer structure, preferably both sides of the laminated layer structure, wherein the closeout ply comprises a sheet of fabric ply, a layer of hoop tow, a bias ply layer, hoop wound fibreglass tow or combination thereof.

22.-23. (canceled)

24. A rim portion of a composite wheel according to claim 1, wherein the fibres comprise carbon fibres.

25. A rim portion of a composite wheel according to claim 1, further comprising a matrix material enveloping the fibres of the stacked laminate, wherein the matrix material comprises a resin based on unsaturated polyester, polyurethane, polyvinyl ester, epoxy, thermoplastics, similar chemical compounds or combinations thereof.

26.-27. (canceled)

28. A composite wheel including a rim portion according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The present invention will now be described with reference to the figures of the accompanying drawings, which illustrate particular preferred embodiments of the present invention, wherein:

[0072] FIG. 1 is a perspective view of a composite wheel including a rim portion according to one embodiment of the present invention.

[0073] FIG. 2 is a more detailed view of the rim to face connection region of the composite wheel shown in FIG. 1.

[0074] FIG. 3 provides a side view of the rim portion of the composite wheel shown in FIGS. 1 and 2 providing the fibre orientation directions of the rim portion.

[0075] FIGS. 4 to 6C provide a cross-sectional schematic representation of the fibre layer layup of various portions of the rim portion of embodiments of the composite wheel shown in FIGS. 1 to 3. A key to the different layers represented in these Figures is provided in FIG. 5(B).

[0076] FIGS. 7 to 12 illustrate the progressive fibre layer layup steps in forming the rim portion according an embodiment of the present invention.

DETAILED DESCRIPTION

[0077] Referring firstly to FIG. 1, there is shown a perspective view of a composite wheel 100 which includes a rim portion 102 according to one embodiment of the present invention. The illustrated composite wheel 100 has been developed by the Applicant as an integrally formed one-piece body. The general process of manufacture of the composite wheel 100 is described in International Patent Publication WO2010/024495A1, the contents of which are to be understood to be incorporated into this specification by this reference. It is noted that formation of the rim portion 102 in that publication is superseded for the configuration of the present invention by the details provided in the present application.

[0078] The illustrated composite wheel 100 includes two main sections:

A). a rim portion 102 comprises an annulus structure onto which a tyre (not illustrated) is mounted; and
B). a face portion 104 comprising a circular hub 106 and a series of spokes 108. The hub 106 includes five fastening apertures 107 configured to receive fastening bolts (not illustrated) used to fix the wheel to a wheel mount of a vehicle. The spokes 108 comprise elongate arms connected to the hub 106 at one end and the rim portion 102 at another end. Whilst a fastening bolt mounting connection is illustrated, it should be appreciated that the hub 106 can be configured for other fastening connections, such as a center mount configuration and other wheel mounting configurations known in the art.

[0079] As described in International Patent Publication WO2010/024495A1, the creation of such a one-piece composite wheel 100 necessitates use of a separate rim portion mould (for example 280, 310 in FIGS. 7 to 12) and face portion mould (For example in part shown as 300 in FIG. 8). In use, the face portion 104 is formed by laying up a first set of fibres, typically embodied in a reinforcement fabric seated in the face portion mould. The rim portion mould includes an inner bucket mould and can use, where applicable, an outer cylindrical mould. The rim portion 102 is formed by laying up a second set of fibres typically embodied in a reinforcement fabric seated in the rim portion mould. The reinforcement fabric from the rim portion mould and the face portion mould are assembled together in a combined mould, with the separate portions being interconnected at a connection point 110. A final moulding process is then undertaken in which matrix material, such as a resin can be injected and/or infused into the reinforcement of the overall wheel form to produce a moulded single piece wheel 100.

[0080] As will be described below, the method of forming the rim portion 102 and its fibre architecture according to the present invention now differs to that described in WO2010/024495A1. The spoke to rim connection 110 is formed through the interconnection of the rim reinforcement and face reinforcement of the rim portion 102 and face portion 104 of the composite wheel 100 whilst laying up the rim portion 102. The fibre layup of the rim portion is also laid up after the face portion 104 layup is completed so that the connection between the face portion 104 and 102 can be included directly in the fibre layup of the rim portion 102.

[0081] FIGS. 3 to 6C show the fibre layup details of a rim portion 102 according to one embodiment of the present invention. The illustrated rim portion 102 comprises an annulus shaped body formed about a central axis of rotation X-X of the composite wheel 100. As shown in FIG. 3, the rim portion 102 also has a circumferential axis C-C extending circumferentially about the central axis X-X and around the rim portion 102. The rim portion 102 has a series of contoured annular features located along the width of that body. The illustrated rim portion 102 firstly includes two annular flanges 201, 202 that radially extend outwardly from or about the distal edges of the rim portion 106. Those flanges 201, 202 comprise an outer flange 201, which is located on the outer edge 205 of the rim portion 102, at or adjacent to the face portion 104 of the composite wheel 100 and an inner flange 202, located on or at the inner edge 206 of the composite wheel 100, which is located closest to the wheel mount of a vehicle (not illustrated) when mounted on a vehicle. The flanges 201, 202 provide the edge stop members which abut and retain the tyre and tyre walls (not illustrated) onto the rim portion 102 and the composite wheel 100. The rim portion 102 also includes two annular beads, comprising an inner safety bead 210 and outer safety bead 211 which are respectively spaced apart from the inner flange 202 and outer flange 201 of the rim portion 102. The safety beads 210, 211 are used to retain the inner edge of the tyre (not illustrated) onto the rim portion 102. In use, the rim of the tyre wall (not illustrated) is seated between the cooperative flange 201, 202 and safety bead 210, 211.

[0082] The illustrated rim portion 102 also includes a drop center 220 comprising a recessed or trench portion of the rim portion 102 located in the illustrated embodiment adjacent to but spaced away from the outer safety bead 211. The recess of the drop center 220 assists in the fitment and removal of a tyre from the rim portion by allowing the rim or bead of the tyre (not illustrated) to be pushed into the recess of the drop center 220 while the other side of the tyre is pulled over and off the opposing flange. It should be appreciated that the recess forming the drop center 220 could be positioned anywhere along the width of the rim portion 102, between the two safety beads 210, 211.

[0083] FIGS. 4 to 6C provide cross-sectional views of the rim portion 102 providing a view of the fibre layup of the rim portion 102. As shown in those figures, the rim portion 102 is formed as a stacked laminate of at least two different fibre layer compositions stacked as alternating layers in this layup. Those layer compositions are: [0084] (1) a hoop tow layer 230 (labelled 0 hoop and 0 tow bundles in key the provided in FIG. 5(B)) comprising elongate fibre tow (see FIGS. 7 to 12) in which the fibres are substantially aligned with the circumferential axis C-C of the rim portion 102; and [0085] (2) a bias ply layer 240 (labelled+/33 NCF fabric in the key provided in FIG. 5(B)) comprising at least one sheet of tow or fabric in which the fibres are substantially orientated at an angle of + or to the circumferential axis of the rim portion. In the illustrated embodiment, is 33. However, it should be appreciated that could be anywhere from 26 to 40 depending on design considerations.

[0086] Each bias ply layer 240 is sandwiched between adjacent hoop tow layers 230 such that each hoop tow layer 230 constrains the adjacent bias ply layer 240 enabling the laminate thickness to be controlled to an extent. The bias ply layers 240 are arranged in the lay up to provide alternating angled fibre directions either side of a hoop tow layer 230. In the illustrated embodiment, consecutive bias ply layers 240 (about a hoop tow layer 230) are therefore arranged in the layup to provide a layer having a fibre orientation angle that is the (+ or ) alternate angle of the fibre orientation of the preceding bias ply layer 240. The resulting laminate stack therefore comprises consecutive layers providing a repetition of [0 (hoop tow layer 230), + (bias ply layers 240), 0 (hoop tow layer 230), (bias ply layers 240)] fibre orientation angles relative to the circumferential axis C-C of the rim portion 102.

[0087] The hoop tow layer 230 provides a fibre orientated or aligned with the circumferential axis C-C of the rim portion 102. This provides hoop strength to the rim portion 102 and stiffness in the barrel or annulus shape of the rim portion 102. The bias ply layer 240 provides angled orientated or aligned fibres, providing strength lateral reinforcement to the structure of the rim. The specific angle used is dependent on the overall configuration of the composite wheel and the rim portion and requisite loadings and the like. A key to the line configurations of each of the layers shown in FIGS. 4 to 6C is provided in FIG. 5(B).

[0088] The aligned fibres in the hoop tow layer 230 typically provides between 40 to 60% of the fibre direction, preferably about 50% of fibre direction in the rim portion 102. Similarly, the bias ply layer 240 typically provides between 40 to 60% of the fibre direction, preferably about 50% of the fibre direction in the rim portion 102.

[0089] As shown in FIGS. 4 and 6A, the main body 251 of the rim portion 102 is a laminate stack comprises consecutive layers providing a repetition pattern or sequence of the combination of 0, + and fibre orientation angles relative to the circumferential axis of the rim portion formed from the a hoop tow layer 230 and bias ply layers 240 outlined above. The inner flange 201, the outer flange 202, the inner safety bead 210 and the outer safety bead 211 and drop center 220 of the composite wheel 100 have different layup configurations, described in more detail below.

[0090] The actual laid up configuration of each of the layers of the rim portion 102 are best illustrated in FIGS. 7 to 12.

[0091] As shown in FIGS. 7 and 8, each hoop tow layer or hoop wound tow layer 230 is formed from an annularly wound elongate fibre tow 232 which is wound around the inner bucket mould 310 of rim mould 280. That elongate fibre tow 232 is wound in hoops around the inner bucket mould 310 and along the width thereof to form the desired thickness and contours of each hoop tow layer 230. The resulting layer comprises a series of overlapping and concentric hoops of the elongate fibre tow 232.

[0092] As best illustrated in FIG. 9, the bias ply layer 240 is formed from a sheet 242 of interconnected unidirectional tow that is stitched together to form a sheet. The tow is orientated at the desired angle in the sheet. Typically, a single continuous bias tow sheet 242 is laid up from the inner flange 201 to the outer flange 202 of the composite wheel 100 to form the respective bias ply layer 240. Each bias ply layer 240 can therefore be formed without butt joins. However, in alternate embodiments the bias plies may not be continuous between both flanges 201, 202, and could be laid up as smaller patches that are installed (possibly in overlapping mosaic like formation) to form the requisite layer. The patches may be overlapped.

[0093] As shown in FIG. 7, a close out ply layer 250 may be used on the inner side of the rim portion 102, which is first applied to the inner bucket mould 310 (of rim mould 280). This closeout ply 250 can comprises a sheet of fabric ply, a layer of hoop tow, a bias ply layer, hoop wound fibreglass tow or combination thereof. The fibre layup of the rim portion 102 can also further include at least one capping layer provided over the final applied hoop tow layer of the fibre layup. The capping layer provides a final layer of reinforcement over the outer surface of the fibre layup, and provides a finishing layer preferably matching the outer surface of adjoining sections of the composite wheel. Like the close out ply layer 250, the capping layer can comprise a sheet of fabric ply, a layer of hoop tow, a bias ply layer, hoop wound fibreglass tow or combination thereof

[0094] As shown in FIGS. 8 and 6B, the outer end 205 of the layup will also include connection sheets or sections 259 (labelled face fabric in the key provided in FIG. 5(B)) from the fibre layup of the face portion 104 which are integrated in the rim portion layup to securely connect the face portion 104 and rim portion 102 together. As shown in FIG. 6B, these can be part of the base layup from the outer flange 201 through to the drop center 220.

[0095] Referring again to FIGS. 4 to 6C, it can be observed that the contoured features of the rim portion are formed from a combination of the contoured configuration of a rim mould (not shown) and from being built up from aggregated hoop wound tow. As shown in FIGS. 5 and 6B and 6C, each of the edge flanges 201 and 202 are built up from an aggregated thickness of hoop wound tow 230. In this respect, the hoop tow layer 230 in each of the edge flanges 201 and 202 locations include additional hoop tow windings to build up the contours of the flange 201, 202. Similarly, the inner safety bead 210 and the outer safety bead 211 are built up from an aggregated thickness of hoop wound tow in one of the hoop tow layers 230.

[0096] As shown in FIG. 5, the layup of the inner flange 202 includes reinforcement layers (labelled 90 NCF fabric in the key provided in FIG. 5(B)) 260 comprising a fibre ply having fibres orientated from 80 to 100 degrees to the circumferential axis of the rim portion. In the illustrated case, the reinforcement layers 260 comprise a fibre ply fibre ply having fibres orientated 90 degree to the circumferential axis C-C of the rim portion 102. Those reinforcement layers 260 extend in the layup along the vertical or upright sections 293 of the inner flange 202 and extend through to the main section of the rim to the inner safety bead 210. Such reinforcement layers 260 assist the prevention of cracking of the laminate in this region.

[0097] The drop center 220 is formed from a combination of a moulded shape formed in the contoured shape of the rim mould 280 (and comprising inner bucket mould 310), and through selective or reduced application of hoop tow layers in the drop center recess, forming a thinner or reduced thickness in that area. The drop center recess 220 therefore has less hoop tow windings than sections adjacent to the drop center recess 220. As shown in FIGS. 11 and 12, any strength reduction from this lower hoop tow layup can be reinforced through the application of at least one reinforcement layer 260 located in the drop center recess 260. In the illustrated embodiment, this reinforcement layer 260 comprises a fibre ply, typically a fabric formed by stitched tow, having fibres orientated from about 90 degree to the circumferential axis of the rim portion, though it should be appreciated that the fibre alignment could be from 80 to 100 degrees to the circumferential axis C-C of the rim portion 102. As shown in FIG. 6C, reinforcement layers 260 extend in the layup through the drop center 220, up through the vertical or upright sections 295 of the drop center and extend towards the outer flange 201.

[0098] Finally, it should be noted that the radially extending sections or flanges (i.e. those sections that are radially extending or aligned with the central axis) of the contoured shape of the rim portion (for example sections 290, 291, 292 in FIGS. 4, 5, 6B and 6C) are formed with reduced or less tow than sections adjacent thereto for lower inter-laminar tension.

[0099] The fibre layup or fibre architecture of the rim portion 102 comprises a multi-layered structure. The number of layers may vary considerably depending on the design of the rim portion and the size and type of composite members. In some embodiments, only a few layers, 4 to 10 layer, preferably 4 to 20 layers, for example, 4, 6, 8, 10, 12, 14, 16, 18 or 20 layers are used. In other embodiments, a higher number, for example 20, 30, 50, 100 or more layers are needed to obtain the desired quality and/or properties of the rim portion 102.

[0100] It should be appreciated wide variety of fibres may be used in the present invention, including but not limited to fibres selected from the group consisting of carbon fibres, glass fibres, aramid fibres, synthetic fibres such as acrylic, polyester, PAN, PET, PE, PP or PBO-fibres, or the like, bio fibres such as hemp, jute, cellulose fibres, or the like, mineral fibres for example Rockwool or the like, metal fibres for example steel, aluminium, brass, copper, or the like, boron fibres or any combination of these. In a preferred embodiment, the fibres comprise carbon fibres.

[0101] The fibre density in each hoop tow layer 230 and bias ply layer 240 can be controlled by forming the various layers out of materials of a selected fibre density. The fibre density in each layer 230, 240 is from 50 to 400 g/m.sup.2, preferably from 180 to 250 g/m.sup.2, more preferably from 180 to 220 g/m.sup.2, yet more preferably about 200 g/m.sup.2.

[0102] The illustrated composite wheel 100 (FIG. 1) is intended to be formed as a unitary body. This involves simultaneous injection and/or impregnation of a matrix material, which in the exemplary embodiment is a resin, into all parts including the rim portion 102, face portion 104 and connection 110 and then curing of each of the portions of the composite wheel 100. The resin used is preferably epoxy-based. However, it should be understood that any suitable resin can be used for example unsaturated polyester, polyurethane, polyvinyl ester, epoxy, thermoplastics, similar chemical compounds or combinations thereof. A variety of resin delivery systems can be used including, but not limited to Resin Infusion and/or Resin Transfer Moulding and/or Vacuum Assisted Resin Transfer Moulding.

[0103] The formed rim portion 102 of the composite wheel 100 therefore also comprises a matrix material enveloping the fibres of the stacked laminate, typically a resin based on unsaturated polyester, polyurethane, polyvinyl ester, epoxy, thermoplastics, similar chemical compounds or combinations thereof. However, it should be appreciated other matrix materials may also be applicable.

[0104] In constructing a composite wheel 100 illustrated in FIG. 1, the composite wheel 100 includes two main mould faces. Firstly, a face mould 300, which is generally radially orientated relative to the axis of rotation of the wheel X-X. Secondly, an inner bucket mould 310, which forms the inside face of the rim portion 102 (FIGS. 7 and 8). The inner bucket mould 310 includes a front face forming the back mould wall of the face portion which is radially orientated relative to the axis of rotation of the wheel X-X. The inner bucket mould 310 is substantially axially aligned to the axis of rotation of the wheel X-X.

[0105] In use, the face portion 104 is laid up with reinforcement with the connection 110 sections for example connection sections or tabs 260 (FIG. 8).

[0106] The rim portion 102 is formed firstly by applying close-out ply or plies (labelled+/45 woven 22 fabric in the key provided in FIG. 5(B)) 250 (if required) to the inner bucket mould 310. The close out ply can comprise a +/45 biased woven fabric. The inner bucket mould 310 is then combined with the preformed face portion lay-up, face mould 300 as shown in FIG. 8. The connection sections 259 connected with the face portion 104 layup are laid onto the close-out ply or plies 250 and a first hoop tow layer 230 is applied over the close-out ply 250 and part of the connection sections or tabs 259. A bias ply layer 240 is then applied, and then alternate layers of hoop tow layer 230 and bias ply layer 240 to build up the rim portion 102 and contoured features thereof as described above. Advantageously, the hoop tow 230 holds the bias ply 240 in the correct position against the tooling during layup. It is intended that this process would be reasonably automated, with some operator input to set the starting point of tows/plies, or to guide a new layer of bias ply over the layup mandrel and set ply clamps, or the like. During layup, a layer of bias ply or plies 240 is fed onto the rim mould 280 and a layer of tows is hoop wound thereon to encapsulate the bias ply in the layup and form a hoop tow layer 230. A second layer of bias ply or plies 240 (in the opposite bias i.e. fibre angle relative to the circumferential axis C-C) is fed onto the layup so that it covers the previous layer of tows 230. That bias ply layer 240 is then covered with a layer of tows hoop wound thereon to encapsulate the bias ply 230 in the layup and form a hoop tow layer 230. This is repeated until the required laminate thickness is achieved.

[0107] The resulting rim layup is a stacked laminate formed from a combination of hoop tows (hoop tow layer 230) and bias plies 240 arranged around the face layup, face mould 300 and bucket mould 301. This stacked laminate is presented to a resin injection station (not illustrated) where a vacuum source and resin injection head are connected to a tool assembly and resin is injected and/or impregnated under pressure into a cavity containing the layup. The resin permeates the fibre of the stacked laminate and cures to form a laminated wheel. After demould, the unfinished moulded wheel can undergo finishing procedures (further drilling, surface finishing, coating and the like).

[0108] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention.

[0109] Where the terms comprise, comprises, comprised or comprising are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other feature, integer, step, component or group thereof.