VEHICLE WHEEL DISC, VEHICLE WHEEL INCLUDING SUCH A WHEEL DISC AND METHOD FOR PRODUCING SUCH A WHEEL DISC AND VEHICLE WHEEL

BACKGROUND OF THE INVENTION

[0001] The present invention relates in general to a vehicle wheel disc and vehicle wheel and in particular to an improved wheel disc, vehicle wheel including such a wheel disc and method for producing such a wheel disc and vehicle wheel.

[0002] Wheels for automotive vehicles may be produced from light weight metals to reduce the weight of the wheels. For example, the vehicle wheels may be produced as a single cast component made from aluminum or alloys thereof. The weight of such wheels may be further reduced by removing mass or material from the wheels. A reduction in the weight of vehicle wheels may have the advantage of increasing the wheel's performance by reducing the unsprung mass of that component of the vehicle.

[0003] However, removing mass from the wheel also may reduce the stiffness and rigidity of the wheel. It is generally desirable to remove mass from the wheel without a significant reduction in stiffness and rigidity. In some situations, the aesthetic look of a reduced mass wheel may not appeal to consumers. Thus, it may be desirable to form the wheel such that a reduced mass is obtained while maintaining the aesthetic appeal of the wheel. SUMMARY OF THE INVENTION

[0004] The present invention relates to an improved wheel disc, vehicle wheel including such a wheel disc and method for producing such a wheel disc and vehicle wheel as illustrated and/or described herein.

[0005] According to one embodiment, the wheel disc may comprise, individually and/or in combination, one or more of the following features, elements, or advantages: a wheel disc for a vehicle wheel including a hub having bolt holes formed therein, wherein the hub defines a wheel axis, and wherein the wheel disc further includes a plurality of spokes radially extending outwardly from the hub, and wherein the wheel disc further includes at least one web disposed between and connected to a pair of adjacent spokes, wherein the web has a vent opening formed therein.

[0006] According to this embodiment, the wheel disc further includes a plurality of webs such that one web of the plurality of webs is disposed between and connected to each of adjacent spokes, wherein each of the webs has a vent opening formed therein.

[0007] According to this embodiment, the webs is co-planar and extend in a planar direction perpendicular to the wheel axis.

[0008] According to this embodiment, the web is continuous such that portions of the web extend completely around the vent opening. [0009] According to this embodiment, the web is non-continuous such that edge portions of the vent opening are disposed along one of spokes.

[0010] According to this embodiment, the web includes an inner portion connected to the hub and proximal ends of the pair of adjacent spokes; and an outer portion connected to distal ends of the pair of adjacent spokes.

[0011] According to this embodiment, the outer portion of the web includes a first portion connected to one of the spokes of the adjacent pair of adjacent spokes, and a second portion connected to the other spoke of the adjacent pair of adjacent spokes.

[0012] According to this embodiment, the outer portion of the web is non- continuous such that the first and second portions of the outer portion are not connected with one another.

[0013] According to this embodiment, the outer portion is adapted to be connected to an outer rim.

[0014] 10. The wheel disc of claim 7, wherein the inner portion of the web includes a first portion connected to one of the spokes of the adjacent pair of adjacent spokes, and a second portion connected to the other spoke of the adjacent pair of adjacent spokes.

[0015] According to this embodiment, the web further includes a first intermediate portion connecting the first portion of the inner portion with the first portion of the outer portion, and a second intermediate portion connecting the second portion of the inner portion with the second portion of the outer portion.

[0016] According to this embodiment, each of the spokes includes V-shaped distal ends defining first and second branches separate from one another, and wherein ends of the first and second branches are adapted to be connected to an outer rim.

[0017] According to another embodiment, the vehicle wheel disc may comprise, individually and/or in combination, one or more of the following features, elements, or advantages: an outer rim defining a wheel axis; and a wheel disc including: a hub having bolt holes formed therein; a plurality of spokes radially extending outwardly from the hub, wherein each of the spokes has a proximal end connected to the hub, and a distal end connected to the rim; and at least one web disposed between and connected to a pair of adjacent spokes, wherein the web has a vent opening formed therein.

[0018] According to this embodiment, the web includes an outer portion connected to distal ends of the pair of adjacent spokes.

[0019] According to this embodiment, the outer portion of the web includes a rim connecting portion which is connected to the rim.

[0020] According to this embodiment, the outer portion of the web includes first and second rim connecting portions spaced from one another. [0021] According to this embodiment, the web further includes an outer circumferential edge positioned between the first and second rim connecting portions.

[0022] According to this embodiment, the outer circumferential edge is spaced from the rim such that a gap exists therebetween.

[0023] According to this embodiment, each of the spokes includes V-shaped distal ends defining first and second branches separate from one another, and wherein ends of the first and second branches are connected to the outer rim.

[0024] According to this embodiment, the wheel disc is configured to be secured to the outer rim by producing the outer rim and the wheel disc by a forming process to produce a one-piece cast vehicle wheel or secured to a separately formed wheel rim by suitable means to produce a fabricated vehicle wheel, wherein the wheel disc and the outer rim of the fabricated vehicle wheel are formed of similar or dissimilar materials.

[0025] Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Fig. 1 is a front elevational view of a first embodiment of a vehicle wheel in accordance with the present invention.

[0027] Fig. 2 is a rear elevational view of the wheel of Fig. 1. [0028] Fig. 3 is a side elevational view of the wheel of Fig. 1.

[0029] Fig. 4 is a front perspective view of the wheel of Fig. 1.

[0030] Fig. 4 A is a front perspective view of an alternate embodiment of a wheel illustrating a different hub configuration.

[0031] Fig. 5 is a rear perspective view of the wheel of Fig. 1.

[0032] Fig. 5A is a rear perspective view of the wheel of Fig. 4A.

[0033] Fig. 6 is a cross-sectional perspective view of the wheel taken along lines 6-6 of Fig. 3.

[0034] Fig. 7 is a cross-sectional view of the wheel generally taken along lines 7-7 of Fig. 1.

[0035] Fig. 8 is a cross-sectional view of the wheel generally taken along lines 8-8 of Fig. 1.

[0036] Fig. 9 is a rear elevational view of the wheel disc separated from the outer rim illustrating connecting portions of the wheel disc to the outer rim.

[0037] Fig. 10 is an enlarged partial perspective view of a portion of the wheel disk of the wheel of Fig. 1 illustrating connecting portions of the wheel disc to the outer rim. [0038] Fig. 10A is an enlarged partial perspective view of a portion of an alternate embodiment of a wheel disk illustrating an alternate connecting portion configuration.

[0039] Fig. 11 is a rear elevational view of a second embodiment of a wheel disc separated from an outer rim illustrating alternate connecting portions of the wheel disc to the outer rim.

[0040] Fig. 12 is a rear elevational view of a third embodiment of a wheel disc separated from an outer rim illustrating alternate connecting portions of the wheel disc to the outer rim.

[0041] Fig. 13 a rear elevational view of a fourth embodiment of a wheel disc separated from an outer rim illustrating alternate connecting portions of the wheel disc to the outer rim.

[0042] Fig. 14 a rear elevational view of a fifth embodiment of a wheel disc separated from an outer rim illustrating alternate connecting portions of the wheel disc to the outer rim.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0043] Referring now to the drawings, there is illustrated in Figs. 1 through 8 a vehicle wheel, indicated generally at 10. The wheel 10 generally incudes an inner wheel disc, indicated generally at 12, and an annular outer rim 14.

Although the invention is illustrated and described in conjunction with the particular vehicle wheel construction disclosed herein, it will be appreciated that the invention can be used in conjunction with other types of vehicle wheel constructions. Also, it will be appreciated that one or more features disclosed in a particular one of the embodiments disclosed herein may be added to and/or omitted from the particular one of the embodiments and/or the other embodiments disclosed herein.

[0044] In a preferred embodiment (and as illustrated herein), the wheel disc 12 and the outer rim 14 are unitarily or monolithically produced, such as for example, as a single casting. After production of the casting, portions of the casting can be machined or otherwise worked to form the wheel 10.

Alternatively, the wheel disc 12 and outer rim 14 may be produced separately, such as separate castings and/or non-castings, and then joined together by any suitable means, to produce a "fabricated" vehicle wheel 10. In this fabricated example, the wheel disc 12 is preferably produced as a single casting.

[0045] The wheel 10 can be produced or cast from any suitable material. For example, the wheel 10 may be an all-cast wheel design formed from aluminum or alloys thereof. Aluminum is advantageous in that it is relatively inexpensive, lightweight, easily machinable, and can provide sufficient rigidity. Other suitable materials in which the wheel 10 can be made of include magnesium, titanium or alloys thereof, steel, carbon fiber and/or composite materials.

[0046] As shown in Fig. 1, the combination of the wheel disc 12 and the outer rim 14 defines a wheel axis X for the wheel 10. The outer rim 14 can have any suitable annular shape for receiving and supporting a tire (not shown). In one embodiment, the outer rim 14 is machined after the wheel 10 is cast to provide a continuous annular shape relative to the wheel axis X for accommodating the tire. It should be appreciated that the outer rim 14 can have any desired diameter and/or shape. The outer rim 14 includes a front facing circumferential edge 15, and a rear facing circumferential edge 16. The outer rim 14 includes a tapered frustoconical sidewall 18 extending inwardly from the front facing circumferential edge 15, as best shown in Fig. 6. The outer rim 14 further includes a generally tubular central wall 19 extending from the end of the sidewall 18. As will be explained in detail below, the sidewall 18 and the central wall 19 provide for attachment or connection locations of the wheel disc 12 to the outer rim 14. As stated above, the wheel 10 may be formed in a single casting such that the attachment or connection locations between the wheel disc 12 and the outer rim 14 are integrally formed together in the casting process.

[0047] The wheel disc 12 is generally comprised of a central hub 20, a plurality of spokes 22, and a plurality of webs 24 that connect with and are disposed between adjacent spokes 22, as will be discussed in detail below. As stated previously, it is preferred that the wheel disc 12 is a single cast component such that the hub 20, the spokes 22, and the webs 24 are all formed together as a single cast.

[0048] The hub 20 is generally defined as the central portion of the wheel disc 12 from which the spokes 22 extend radially outward therefrom. The hub 20 defines a front face 26 (or front surface), as seen in Figs. 1 and 4, and a rear face 28 (or rear surface), as seen in Figs. 2 and 5. The front face 26 is located on the outboard side of the wheel 10 when mounted on a vehicle. The rear face 28 is located on the inboard side of the wheel 10 when mounted on a vehicle. The hub 20 functions as a wheel mounting portion or center mounting portion of the wheel 10 for connecting with an axle (not shown) via a plurality of lug bolts (not shown) and lug nuts (not shown). In a preferred embodiment, the front face 26 of the hub 20 has a planar surface perpendicular to the wheel axis X. In a preferred embodiment, the front face 26 of the hub 20 is also planar and flush with front surfaces of the webs 24, as will be discussed below. The rear face 28 of the hub 20 may have any suitable shape and generally conforms to and blends in with each of the spokes 22 at their mating locations. Thus, the rear face 28 of the hub 20 has a relatively erratic curvature profile.

[0049] The hub 20 includes a centrally located pilot aperture or hub hole 30. The hub hole 30 extends along the wheel axis X. The hub hole 30 may accommodate a portion of the axle and/or receive a protective/decorative cap (not shown). A plurality of lug bolt receiving holes 32 are circumferentially spaced around the hub hole 30 and wheel axis X. In the illustrated embodiment, the hub 20 includes five lug bolt receiving holes 32, which are preferably provided in the hub 20 in alignment with a respective one of each of the spokes 22. Alternatively, the number and/or location of the lug bolt receiving holes 32 may be other than illustrated if so desired. The lug bolt receiving holes 32 receive the lug bolts for securing the vehicle wheel 10 with lug nuts on the axle of an associated vehicle.

[0050] The details of the lug bolt receiving holes 32 will now be discussed. As best shown in Fig. 6, the lug bolt receiving holes 32 define a large diameter bore 33 formed in the front face 26 of the hub 20, and a smaller diameter bore 34 formed in the rear face 28 of the hub 20. Generally, the smaller diameter bores 34 are sized to receive threaded lug bolt shafts (not shown) while the larger diameter bores 33 are sized to receive lug nuts (not shown) and to accommodate a wrench or other tool for fastening the lug nuts to the lug bolts. As best shown in Fig. 5, the smaller diameter bores 34 may be formed in tubular shaped structures 36 formed in the rear face 28 of the hub 20. Of course, the smaller diameter bores 34 may be formed in any suitable structural formation on the rear face 28 of the hub 20. The first and second bores 32 and 34 define a circular ledge 37 (as shown in Fig. 6) therebetween having a front facing surface. The ledge 37 provides for a contact and mounting surface upon which a lug nut (not shown) is tightened on a corresponding lug bolt to clamp or mount the wheel 10 to the axle. The ledge 37 may be a planar surface perpendicular to the wheel axis X, or may be chamfered or formed as a curved surface to accommodate the contacting or mating portion of the lug nut. Alternatively, the lug bolt receiving holes 32 may be formed as a single hole or bore such that the lug nut will simply contact and engage with the front face 26 of the hub 20 when the wheel 10 is mounted.

[0051] Although the lug bolt receiving holes 32 may be formed to any size, in a preferred embodiment the diameter of the large diameter bore 33 is within the range of about 20 millimeters to about 50 millimeters. It is noted that due to the shape and profile of the spokes 22 and the hub 20, openings 38 (as shown in Fig. 6) may be formed through the cylindrical sidewalls of the larger diameter bores 33 such that the bores 33 do not have a continuous and smooth cylindrical sidewall. Alternatively, the hub 20 of the wheel disc 12 may be designed such that the openings 38 are not formed therein, thereby providing smooth cylindrical sidewalls of the lug bolt receiving holes 32. For example, there is illustrated in Figs. 4A and 5A an alternate embodiment of a wheel 10' having a hub 20' having a generally heftier or fuller configuration. This configuration adds material to the hub 20' surrounding lug bolt receiving holes 32' as compared to the hub 20 of the wheel disc 12. Thus, the sidewalls of the lug bolt receiving holes 32' may have side openings therein. This configuration may also provide for a relatively flat planar rear face 28' of the hub 20' (Fig.

5 A) which may be perpendicular to its wheel axis X'. [0052] In the illustrated embodiment, the wheel disc 12 includes five spokes 22 which are shown as being formed integral with the hub 20 and the outer rim 14. Alternatively, the number of the spokes 22 may be other than illustrated if so desired. For example, the vehicle wheel 10 may include less than five spokes 22 or more than five spokes 22. Alternatively, the spokes 22 may be individually formed and secured to the outer rim 14 and the hub 20 by any suitable means and the outer rim 14 may be formed integral but separate from the hub 20 and joined thereto by any suitable method.

[0053] As best shown in Figs. 2 and 5, the spokes 22 are preferably essentially identical in structure with one another. Alternatively, one or more the spokes 22 may have differing shapes dependent of the placement about the hub 20. Each of the spokes 22 includes a distal end, indicated generally at 50, which connect, secure, or otherwise join the spokes 22 to the outer rim 14. Each of the spokes 22 also includes a proximal end, indicated generally at 52 which connect, secure, or otherwise join the spokes 22 to the hub 20. The spokes 22 can have any suitable shape radially extending from the hub 20 to the outer rim 14. As will be discussed in detail below, the illustrated embodiment of the distal end 50 of each of the spokes 22 has a V-shaped forked configuration. In the illustrated embodiment, each of the spokes 22 are essentially identical in structure. Although the spokes 22 may be formed with a constant width and depth as extending along the radial direction, it is noted that in the illustrated embodiment the spokes 22 do not have a constant cross- sectional shape as extending along the radial direction and thus have differing widths and depths at varying positions relative to the radial distance from the hub 20 and the outer rim 14. Additionally, it is noted that many portions of the spokes 22 have gradual curved features especially on the rear face or inboard side of the wheel 10.

[0054] To demonstrate the differing widths of portions of the spokes 22 along the radial length, there is illustrated in Fig. 2, three widths Wi, W2, and W3, taken along various locations along the length of one the spokes 22. The width Wi is located generally at the proximal end 52 of the spoke 22 and has the narrowest width compared to the other widths W2, and W3. The spoke 22 generally bellows slightly outwardly in a radial direction from the proximal end 52 towards a central portion 54 of the spoke 22, as generally shown at width W2. Thus, the width W2 is greater than the width Wi. The spoke 22 then generally narrows to a width W3 towards the V-shaped forked distal end 50 of the spoke 22. Of course, the illustrated embodiment of the spokes 22 is only one example a suitable structure of a spoke 22 arrangement. In a preferred embodiment, the widths Wi, W2, and W3, are within a range of about 13 millimeters to about 42 millimeters. In a more preferred embodiment, the widths Wi, W2, and W3, are within a range of about 18 millimeters to about 37 millimeters.

[0055] A stated above, the spokes 22 can have any suitable shape and need not have a constant cross-sectional shape. As shown in Fig. 7, the rear portion of each of the spokes 22 can have an inward curve defining varying depths along the length of the spokes. As such there is illustrated in Fig. 7 three examples of depths Di, D2, and D3 taken along various locations along the length of one of the spokes 22. The depth Di is generally taken at the proximal end 52 of the spoke 22 which connects with the hub 20. The Depth D2 is generally taken along the central portion 54 of the spoke 22 and has the narrowest depth. The depth D3 is generally taken along the distal end 50 of the spoke 22 and has the longest depth of this illustrated embodiment. As shown in the illustrated embodiment, the depth D2 is about half of that of the depths Di and D3. The narrowing of the spoke 22 along its central portion 54 helps to reduce mass of the spoke 22. In a preferred embodiment, the depths Di, D2, and D3 are within the range of about 10 millimeters to about 110 millimeters. In a more preferred embodiment, the depths Di, D2, and D3 are within the range of about 30 millimeters to about 90 millimeters.

[0056] As best shown in Figs. 2 and 5, the illustrated preferred embodiment of each of the spokes 22 include a V-shaped fork configuration. More specifically, each spoke 22 includes a first branch 60 and a second branch 62 stemming from the central portion 54 at its distal end 50. The width of the branches 60 and 62 are generally less than the width of the region of the spoke 22 from where they branch off of. Preferably, the branches 60 and 62 are similar in structure with one another with the exception of being mirror imaged from one another. The first and second branches 60 and 62 each include an end portion 60a and 62a, respectively, that connects the distal end 50 of the respective spoke 22 to the outer rim 14. In the embodiment wherein the wheel 10 is a single cast such that the wheel disc 12 is integrally formed with the outer rim 14, the end portions 60a and 62a are integrally formed between the outer rim 14 and the branches 60 and 62.

[0057] There is illustrated in Fig. 10 an enlarged partial perspective view of a portion of the wheel disk 12 (shown separated from the outer rim 14) showing connecting portions, indicated and highlighted generally at 70, 72, 74, and 76, of the wheel disc 12 to the outer rim 14. The end portions 60a and 62a of the branches 60 and 62, respectively correspond with the connecting portions 70 and 72 and are illustrated with section lines showing the disconnection of the wheel disc 12 from the outer rim 14. The end portions 60a and 62a are connected to portions of the outer rim 14, such as for example, the sidewall 18 and central wall 19. This connection can be seen in the cross- sectional view of Fig. 8. Note that portions of the sectioned spoke 22 have been removed from Fig. 8 for clarity. It is also noted that the connecting portions 74 and 76 will be discussed below with respect to the webs 24.

[0058] The V-shaped forked configuration of the distal end 50 of the spokes 22 provides for a relatively wide attachment or connection point between the end portions 60a and 62a. This wide connection point provides for a more rigid and durable connection compared to a single ended spoke connection. Additionally, the use of two branches 60 and 62 with a gap therebetween reduces the mass of the spokes 22 compared to single ended spokes having a wide connecting portion.

[0059] As stated above, the wheel disc 12 preferably includes membranes or webs 24 that connect with and are disposed between adjacent spokes 22. As such, the illustrated embodiment of the wheel disc 12 includes five webs 24. Each of the webs 24 includes a relatively large vent opening 80 formed therein. Of course, the webs 24 can include any number of vent openings or may be formed with no vent openings at all. The webs 24 can generally be described as relatively thin membranes which span between adjacent spokes 22. As such, there is illustrated in Fig. 7 three examples of thickness ti, t2, and t3 taken along various locations of a web 24 illustrated therein. In a preferred embodiment, the thicknesses ti, t2, and t3 are within the range of about 0 millimeters to about 25 millimeters. In a more preferred embodiment, the thicknesses ti, t2, and t3 are within the range of about 2 millimeters to about 15 millimeters. Note that the depths Di, D2, and D3 of the spokes 22 are much greater than the thicknesses ti, t2, and t3 of the webs 24. In a preferred embodiment, the thickness of the webs 24 are about five times thinner (or more) than the depth of the spokes 22. Alternatively, the thickness of the webs 24 can be other than about five times thinner than the depth of the spokes 22. For example, the thickness of the webs 24 can be more than five times thinner than the depth of the spokes 22 or the thickness of the webs 24 can be less than five times thinner than the depth of the spokes 22.

[0060] The webs 24 may also extend between the hub 20 and adjacent to or directly connected to the outer rim 14. As will be described in detail below, portions of the webs 24 may be connected to or integrally formed with portions of the outer rim 14. As best shown in Figs. 1 and 4, the webs 24 preferably have front faces 82 which are co-planar and flush with the front face 26 of the hub 20 and with front faces 84 of the spokes 22 to cooperatively provide for a planar flat front of the wheel disc 12. Of course, the hub 20, the spokes 22, and the webs 24 may be formed with curvatures of contours therein such that the front face of the wheel disc 12 is not planar. As best shown in Figs. 1 and 4, the addition of the webs 24 provides the illusion of a relatively large surfaced front face of the wheel disc 12 (minus the vent openings 80) such that the widths of the spokes 22 of the wheel disc appear larger than what they actually are.

[0061] While the webs 24 may each be described as preferably being a single continuously extending membrane, having a vent opening 80 formed therein, that extends between adjacent spokes 22, the webs 24 may also be described as having various portions which are interconnected forming the totality of the web 24. Referring now to Fig. 9, the illustration is a rear elevational view of the wheel disc 12 shown separated from the outer rim 14. As shown, each of the webs 24 is structurally similar with one another. Thus, only a single web 24 will be described and referenced relative the description of the wheel disc of Fig. 9. The web 24 generally includes an inner portion 100, an outer portion 102, and first and second intermediate portions 104 and 106.

[0062] The inner portion 100 of the web 24 is generally connected to the hub 20 and the proximal ends 52 of adjacent spokes 22. The inner portion 100 includes a central portion 110 connected to the hub 20. A first leg portion 112 extends from the central portion 110 in a generally radially outwardly direction and connects with the proximal end 52 of an adjacent spoke 22. A second leg portion 114 extends from the central portion in a generally radially outwardly direction and connects with the proximal end 52 of the opposed adjacent spoke 22.

[0063] The outer portion 102 of the web 24 is generally connected to the distal ends 50 of adjacent spokes 22. The outer portion 102 of the web 24 includes a first wing portion 120 generally connected to the distal end 50 of an adjacent spoke 22. A second wing portion 122 of the web 24 is generally connected to the distal end 50 of the opposed adjacent spoke 22. The first and second wing portions are connected together via a central connecting portion 124.

[0064] The web 24 further defines the first intermediate portion 104 which joins the first leg portion 112 of the inner portion 100 with the first wing portion 120 of the outer portion 102. In the embodiment shown in Fig. 9, the first intermediate portion 104 is a relatively narrow band of membrane attached to the central portion 54 of the adjacent spoke 22. The web 24 further defines the second intermediate portion 106 which joins the second leg portion 114 of the inner portion 100 with the second wing portion 122 of the outer portion 102. In the embodiment shown in Fig. 9, the second intermediate portion 106 is a relatively narrow band of membrane attached to the central portion 54 of the opposed adjacent spoke 22.

[0065] As shown in Fig. 9, the inner portion 100, the outer portion 102, and the first and second portions 104 and 106 form a continuous membrane surrounding a continuous edge 130 of the vent opening 80. In this preferred embodiment, the web 24 provides added rigidity to the wheel disc 12 in the region between adjacent spokes 22.

[0066] The outer portion 102 also defines an outer circumferential edge 140 extending along the radially outwardly most regions of the first wing portion 120, the central connecting portion 124, and the second wing portion 122. The circumferential edge 140 has a generally arcuate shape mirroring the arcuate curve of the circumferential edge 15 of the outer rim 14. It is noted that the illustrated embodiment of the circumferential edges 140 of the webs 24 have a rough, jagged, or uneven profile across its length to provide for an aesthetically pleasing or unique appearance. Of course, the circumferential edges 140 may have a smooth arcuate profile if so desired (see Figs. 11 and 12).

[0067] The circumferential edges 140 of the webs 24 may be connected to outer rim 14 or unattached thereto leaving a gap between the circumferential edges 140 and the outer rim 14. In the illustrated embodiment of the wheel disc 12, portions of the webs 24 are attached to the outer rim 14. As mentioned above, each of the webs 24 include connecting portions, indicated generally at 74 and 76 (see also Fig. 10). The connecting portions 74 and 76 are generally located at opposite ends of the circumferential edge 140 of the respected wing portions 120 and 122 of the web. Of course, the connecting portions 74 and 76 could be located at any suitable location or with any suitable number of connecting portions or points. It should be understood that many different connecting portion configurations may be used to connect the webs 24 to the outer rim 14. Figs. 11, 12, and 13 are examples of different configurations. In the illustrated embodiment of the wheel disc 12 of Figs. 1 through 10, there are four connecting portions 70, 72, 74, and 76 corresponding to each spoke 22. Thus, the number of connecting portions corresponds to the number of spokes 22 that the wheel disc 12 contains.

[0068] There is illustrated in Fig. 10A an alternate embodiment of a wheel disc 141 showing an alternate connecting portion configuration. A pair of connecting portions, indicated and highlighted generally at 142 and 143, connect the wheel disc 141 to the outer rim (not shown). Each of the connecting portions 142 and 143 continuously connect end portions 144a and 145a of branches 144 and 145, respectively, of a spoke 146, as well as portions 147 and 148 of circumferential edges of corresponding webs to the outer rim. Thus, the connecting portions 142 and 144 shown in Fig. 10A have a greater connecting area as compared to the spaced connecting portions 70, 72, 74, and 76 of the embodiment illustrated in Fig. 10.

[0069] There is illustrated in Fig. I l a second embodiment of a wheel disc, indicated generally at 150. The wheel disc 150 is a five spoke configuration and may be similar in structure and function as the wheel disc 12 described above. One of the differences is that the wheel disc 150 includes webs 152 each having three connecting portions, indicated generally at 160, 162, and 164, as compared to the two connecting portions 74 and 76 illustrated in the wheel disc 12 of Fig. 9. The addition of the extra connecting portion 162 may provide greater rigidity of the wheel disc 150 compared to the similar wheel disc 12. Another difference of the wheel disc 150 is that each of the webs 152 includes an outer circumferential edge 168 having a smooth arcuate curvature or profile as compared to the jagged or uneven circumferential edge 140 of the wheel disc 12, as shown in Fig. 9. In a preferred embodiment, the outer circumferential edge 168 of the wheel disc 150 matches the curvature of the adjacent portion of the annular outer rim (not shown).

[0070] There is illustrated in Fig. 12 a third embodiment of a wheel disc, indicated generally at 180. The wheel disc 180 is a five spoke configuration and may be similar in structure and function as the wheel discs 12 and 150 discussed above. One of the differences is that the wheel disc 180 includes webs 182 each having a single arcuate connecting portion, indicated generally at 184. The connecting portion 184 generally extends along the entire arcuate length of a circumferential edge 186 of each of the webs 182. This configuration may provide even greater rigidity as compared to the wheel discs 12 and 150.

[0071] There is illustrated in Fig. 13 a fourth embodiment of a wheel disc, indicated generally at 200. The wheel disc 200 is a five spoke configuration and may be similar in structure and function as the wheel discs 12, 150, and 180 discussed above. The wheel disc 200 includes pairs of connecting portions 202 and 204 similar to the connecting portions 74 and 76 of the wheel disc 12. The wheel disc 200 illustrates an example of non-continuous webs. Unlike the wheel disc 12, the wheel disc 200 does not include webs 24 each having portions that extend completely around a vent opening 80 in a continuous manner. Instead, the wheel disc 200 includes five web regions, indicated generally at 210, having non-connecting portions such that breaks or gaps 211 are formed around corresponding vent openings 212 of the wheel disc 200. For example, each of the web regions 210 includes non-contacting first and second outer wing portions 214 and 216 lacking an interconnecting central connecting portion, such as the central connecting portion 124 of the webs 24 of the wheel disc 12. Additionally, the web regions 210 of the wheel disc 200 lack intermediate portions connecting the wing portions 214 and 216 to leg portions 222 of an inner web portion 224.

[0072] There is illustrated in Fig. 14 a fifth embodiment of a wheel disc, indicated generally at 200'. The wheel disc 200' is a five spoke configuration and may be similar in structure and function as the wheel disc 200 discussed above with respect to Fig. 13. Note that similar structural features of the wheel disc 200' with respect to the wheel disc 200 will be indicated by similar reference numbers with the addition of a prime (') added to the reference numbers for the wheel disc 200'. One of the differences between the wheel discs 200 and 200' is that the wheel disc 200' includes connecting portions 202' and 204' which extend along the entire arcuate length of the outer circumferential edge of each the wing portions 214' and 216'. This configuration is similar to the connecting portions 184 for the wheel disc 180 of Fig. 12.

[0073] The embodiments of the various wheels and wheel discs described herein offer several advantages over conventionally known wheels. The embodiments of the wheel discs described herein were designed by a topology optimization methodology to obtain such advantages. For example, it is conventionally known that to increase the stiffness of the wheel, the mass of the wheel is generally increased. However, the wheel embodiments described herein have obtained an increase in stiffness while reducing the mass or weight of the wheel. It has been found that an increase in stiffness of about 105% can be obtained while reducing the weight by about 22% compared to conventionally known similar sized and similar material wheels. These advantages can be obtained by utilizing the thin webs or membranes connecting adjacent spokes near the hub and/or rim junctions. These advantages are particular useful for wheels specifically designed for electric vehicles. Wheels for electric vehicles generally demand a relatively low weight or mass so that longer battery range distance can be obtained in such vehicles. Additionally, high stiffness of the wheels is preferred to help reduce NVH (Noise vibration and Harshness) created by the tire/wheel interaction. Since electrical vehicles are often less noisy compared to combustion engine vehicles, the perception of noise generated by the wheels can be more readily heard by the vehicle occupants and thus a reduction in wheel noise is greatly beneficial. The embodiments of the wheels described herein can be utilized for all types of wheel designs such as wheels and/or wheel discs manufactured in alloys such as magnesium, aluminum, steel, and/or a composite. Additionally, the embodiments of the wheels described herein are applicable to vehicle wheels having various dimensions such as wheels having diameters from about 381 millimeters (15 inches) to about 610 millimeters (24 inches), and having widths from about 88.9 millimeters (3.5 inches) to about 300 millimeters (11.8 inches).

[0074] The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.