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 includes a hub having bolt holes formed therein, wherein the hub defines a wheel axis. A plurality of spokes extends radially outward from the hub, wherein each of the plurality of spokes has a bifurcated distal end defining first and second prongs spaced from one another in a circumferential direction. An outer web extends radially outwardly from the distal end of each of the spokes, wherein the outer webs are configured to connect with an outer rim.

[0006] According to this embodiment, the outer webs extend in a circumferential direction from the distal ends of each of the spokes.

[0007] According to this embodiment, inner portions of the outer webs extend between the first and second prongs of the plurality of spokes in a circumferential direction.

[0008] According to this embodiment, an opening is formed in at least one of the inner portions of the outer webs.

[0009] According to this embodiment, a continuous web edge is formed encircling the opening. [0010] According to this embodiment, outer portions of the outer webs extend circumferentially outwardly from the first and second prongs of the plurality of spokes.

[0011] According to this embodiment, the wheel disc further includes a plurality of arcuate connecting webs such that an arcuate connecting web extends between adjacent outer portions of the outer webs.

[0012] According to this embodiment, the arcuate connecting webs are configured to be connected with the annular rim.

[0013] According to this embodiment, the plurality of spokes defines an outboard front side and an inboard rear side opposite the outboard front side in a direction along the wheel axis, and wherein the outer webs extend radially outwardly from each of the inboard rear sides of the distal ends of the plurality of spokes.

[0014] According to this embodiment, the outboard front side of the distal ends of the plurality of spokes are spaced from the outer rim such that a gap exists between the distal ends and the outer rim.

[0015] According to this embodiment, the outboard front side of the distal ends of the plurality of spokes are connected to the outer rim.

[0016] According to this embodiment, the outer webs each include an arcuate shaped connection portion connecting the distal ends of the plurality of spokes to the outer rim. [0017] According to this embodiment, the wheel disc further includes a plurality of inner webs such that one web of the plurality of webs is disposed between and connected to each of adjacent spokes.

[0018] According to this embodiment, the plurality of inner webs and the outer webs define a plurality of vent openings.

[0019] According to this embodiment, a continuous web edge is formed encircling the vent openings.

[0020] According to this embodiment, the plurality of inner webs is connected to the hub and proximal ends of the pair of adjacent spokes.

[0021] According to this embodiment, the inner webs each include: 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.

[0022] According to this embodiment, the wheel disc further includes a plurality of intermediate webs connecting the outer webs to the inner webs.

[0023] According to this embodiment, the intermediate webs are located adjacent the distal ends of the plurality of spokes.

[0024] According to this embodiment, an opening is formed in at least one of the inner webs. [0025] According to this embodiment, each of the spokes has a cross- sectional width which varies along the radially extending length of the spoke.

[0026] According to this embodiment, each of the spokes has a central width spaced from the hub which is wider than the width of the spoke adjacent the hub.

[0027] 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

[0028] Fig. 1 is a front perspective view of a first embodiment of a vehicle wheel in accordance with the present invention.

[0029] Fig. 2 is a rear perspective view of the wheel of Fig. 1.

[0030] Fig. 3 is a front elevational view of the wheel of Fig. 1.

[0031] Fig. 4 is a rear elevational view of the wheel of Fig. 1.

[0032] Fig. 5 is a side elevational view of the wheel of Fig. 1.

[0033] Fig. 6 is a cross-sectional perspective view of the wheel taken along lines 6-6 of Fig. 1. [0034] Fig. 7 is a cross-sectional view of the wheel generally taken along lines 7-7 of Fig. 3.

[0035] Fig. 8 is a front elevational view of a second embodiment of a vehicle wheel in accordance with the present invention.

[0036] Fig. 9 is a front elevational view of a third embodiment of a vehicle wheel in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0037] Referring now to the drawings, there is illustrated in Figs. 1 through 7 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.

[0038] In a preferred embodiment (and as illustrated herein), the wheel disc 12 and the outer rim 14 are unitarily or monolithically produced or formed, 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.

[0039] 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.

[0040] 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. In a preferred embodiment, the outer rim 14 has an outer diameter within the range of about 381 millimeters (15 inches) to about 610 millimeters (24 inches).

[0041] As best shown in Figs. 6 and 7, the outer rim 14 includes a front facing circumferential edge 15, and a rear facing circumferential edge 16. The outer rim 14 includes a chamfered or tapered frustoconical sidewall 18 extending inwardly from the front facing circumferential edge 15. The outer rim 14 further includes a generally tubular or cylindrical central wall 19 extending from the end of the sidewall 18. It is noted that the central wall 19 need not be perfectly tubular or cylindrical but may include slight curvatures or bends therein. As will be explained in detail below, the central wall 19 provides 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 or formation such that the attachment or connection locations between the wheel disc 12 and the outer rim 14 are integrally formed together in the forming process.

[0042] The wheel disc 12 is generally comprised of a central hub 20, a plurality of spokes 22, and a plurality of webs. In the illustrated embodiment, a plurality of inner webs 24 connect with and are disposed between adjacent spokes 22, as will be discussed in detail below. Additionally, a plurality of outer webs 25 extend radially outwardly from the spokes 22 connecting to the central wall 19 of the outer rim 14, 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 and 25 are all formed together as a single cast.

[0043] The hub 20 is generally defined as the central portion of the wheel disc 12 from which the spokes 22 extend radially outward therefrom. In the illustrated embodiment, the hub 20 has a generally pentagonal shape when viewing the front of the wheel 10. The hub 20 defines an outboard front face 26 (or front surface), as seen in Figs. 1, 3, 6 and 7, and a circular inboard rear face 28 (or rear surface), as seen in Figs. 2, 4, and 6 and 7. 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, as best shown in Fig. 7. In a preferred embodiment, the front face 26 of the hub 20 is also planar and flush with front surfaces of the spokes 22, as will be discussed below. The rear face 28 of the hub 20 may have any suitable shape, such as circular best shown in Figs. 2 and 4. In the illustrated embodiment, the rear face 28 of the hub 20 is also a generally planar surface perpendicular to the wheel axis X. The hub 20 may have any suitable thickness or depth DH, as indicated in Fig. 7, extending between the front and rear faces 26 and 28. In a preferred embodiment, the depth DH is within a range of about 40 millimeters to about 100 millimeters. In a more preferred embodiment, the depth DH is within a range of about 60 millimeters to about 80 millimeters.

[0044] 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 the 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.

[0045] The details of the lug bolt receiving holes 32 will now be discussed.

As best shown in Figs. 6 and 7, 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. The bores 33 and 34 define a circular ledge 37 therebetween.

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. 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.

[0046] The lug bolt receiving holes 32 may also include an optional slot 38 formed in the larger diameter bores 33 and/or smaller diameter bores 34. The purpose of the key slot 38 is to remove additional mass, when it is not strictly needed. The combination of the mass removal due to key slot 38 on all lug bolt receiving holes 32 can reach around 100g on the wheel.

[0047] In the illustrated embodiment, the wheel disc 12 includes five spokes 22 which are shown as being formed integral with the hub 20 and extending radially outwardly therefrom. 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.

[0048] As best shown in Figs. 1 and 3, 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. 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 bifurcated 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.

[0049] To demonstrate the differing widths of portions of the spokes 22 along the radial length, there is illustrated in Fig. 3, a couple of widths Wj and W2 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 generally has the narrowest width compared to the other widths of the spoke 22. As viewing Fig. 3, the spoke 22 bellows slightly outwardly and increases in width along the outwardly radial direction towards the distal end 50 of the spoke 22. Just prior to bifurcation of the spoke 22, the spoke has a width W2. The width W2 is greater than the width Wi. 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 width Wi is within a range of about 23 millimeters to about 33 millimeters. In a more preferred embodiment, the width Wi is within a range of about 18 millimeters to about 38 millimeters. In a preferred embodiment, the width W2 is within a range of about 43 millimeters to about 53 millimeters. In a more preferred embodiment, the width W2 is within a range of about 38 millimeters to about 58 millimeters.

[0050] A stated above, the spokes 22 can have any suitable shape and need not have a constant cross-sectional shape. The spokes 22 define an outboard front side 56 and an inboard rear side 58. In the illustrated embodiment, the outboard front side 56 has a planar shape perpendicular to the wheel axis X. The outboard front side 56 may be co-planar with the front face 26 of the hub 20, as best 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 Di generally has the longest depth of this illustrated embodiment. The depth D2 is generally taken along a central portion 54 of the spoke 22 adjacent the bifurcated distal end 50. The central portion 54 may be generally defined as a portion of the spoke 22 between the proximal end 52 and the distal end 50. The depth D3 is generally taken within the bifurcated distal end 50 of the spoke 22 and generally has the narrowest depth. As shown in the illustrated embodiment, the depth D3 is a little more than half of the depth DH of the hub 20. The narrowing of the spoke 22 along its central portion 54 helps to reduce mass of the spoke 22. In a preferred embodiment, the depth Di is within a range of about 48 millimeters to about 78 millimeters. In a more preferred embodiment, the depth Di is within a range of about 60 millimeters to about 66 millimeters. In a preferred embodiment, the depth D2 is within a range of about 39 millimeters to about 59 millimeters. In a more preferred embodiment, the depth D2 is within a range of about 40 millimeters to about 48 millimeters. In a preferred embodiment, the depth D3 is within a range of about 25 millimeters to about 56 millimeters. In a more preferred embodiment, the depth D3 is within a range of about 36 millimeters to about 46 millimeters.

[0051] As best shown in Figs. 1 and 3, the illustrated preferred embodiment of each of the spokes 22 include a forked or bifurcated configuration. More specifically, the distal ends 50 of each spoke 22 include a first prong 60 and a second prong 62 generally stemming radially outwardly from the central portion 54 to its distal end 50. The width of the prongs 60 and 62 are generally less than the width of the region of the spoke 22 from where they branch off. As shown in Fig. 3, the prongs 60 and 62 at their generally thickest have a width W3. In a preferred embodiment, the width W3 is within a range of about 6 millimeters to about 26 millimeters. In a more preferred embodiment, the width W3 is within a range of about 12 millimeters to about 20 millimeters.

[0052] Preferably, the prongs 60 and 62 are similar in structure with one another with the exception of being mirror imaged from one another. The first and second prongs 60 and 62 each include outermost ends 60a and 62a. In the illustrated embodiment of Fig. 7, the ends 60a and 62a are spaced from the central wall 19 of the outer rim 14 by a gap G. Thus, the distal ends 50 of the spokes 22 are not directly connected to the outer rim 14 in the illustrated embodiment of the wheel 10 shown in Figs. 1 through 7. As will be explained in detail below, the distal ends 50 of the spokes 22 are indirectly connected to the outer rim 14 via a portion of the outer web 25 extending from the inboard rear side 58 of the spokes 22 to the central wall 19 of the outer rim 14.

[0053] As stated above, the wheel disc 12 preferably includes a plurality of membranes or webs that connect with the spokes 22. The wheel disc 12 generally includes the plurality of inner webs 24 and the plurality of outer webs 25. The inner webs 24 generally extend between adjacent spokes 22. The outer webs 25 generally extend radially outwardly from the distal ends 50 of the spokes 22 to connect the spokes 22 to the outer rim 14. As such, the illustrated embodiment of the wheel disc 12 includes five inner webs 24 and five outer webs 25. Although the details of the inner and outer webs 24 and 25 will be described in detail below, the inner and outer webs 24 and 25 can generally be described as relatively thin membranes which span between adjacent spokes 22 and/or the outer rim 14. As shown in Fig. 7, the inner web 24 has a general thickness ti. The outer web 25 has a general thickness t2. Of course, either of the inner web 24 and the outer web 25 may have a generally constant thickness or a varying thickness. In a preferred embodiment, the thicknesses ti and t2 are within the range of about 2 millimeters to about 12 millimeters. In a more preferred embodiment, the thicknesses ti and t2 are within the range of about 4 millimeters to about 7 millimeters. Note that the depths Di, D2, and D3 of the spokes 22 and the depth DH of the hub 20 are preferably much greater than the thicknesses ti and t2 of the webs 24 and 25. In the illustrated embodiment, the thickness of the webs 24 are about five times thinner (or less) than the depth of the spokes 22. Of course, the webs 24 and 25 may have any suitable thickness relative to the depths of the spokes 22. An advantage of relatively thin webs 24 and 25 is a reduction in mass of the wheel 10 while maintaining sufficient rigidity of the wheel disc 12. [0054] While the inner and outer webs 24 and 25 may be described as single or multiple membranes having various openings formed therein, the inner and outer webs 24 and 25 may also be described as having various portions which are interconnected forming the totality of the webs 24 and 25. In a preferred embodiment, each of the five inner webs 24 are structurally similar with one another. Similarly, each of the five outer webs 25 are structurally similar with one another. Thus, only a single inner web 24 and a single outer web 25 will be described and referenced relative the description of the wheel disc 12.

[0055] Referring to Fig. 3, the inner web 24 has a general U-shaped closed configuration and is generally connected to the hub 20 and the proximal ends 52 of adjacent spokes 22. More specifically, the inner web 24 includes a central portion 80 connected to the hub 20. A first leg portion 82 extends from the central portion 80 in a generally radially outwardly direction and connects with the proximal end 52 of an adjacent spoke 22. A second leg portion 84 extends from the central portion 80 in a generally radially outwardly direction and connects with the proximal end 52 of the opposed adjacent spoke 22. The inner web 24 may have any suitable size. In the illustrated embodiment referenced in Fig. 3, the inner web 24 has a radial length A extending radially outwardly from the hub 20. In a preferred embodiment, the length A is within a range of about 44 millimeters to about 84 millimeters. In a more preferred embodiment, the length A is within a range of about 59 millimeters to about 69 millimeters.

[0056] An optional opening 88 may be formed in the inner web 24. The opening 88 reduces mass of the wheel disc 12 and increase the stiffness. The opening 88 can have any shape and may have any size. As referenced in Fig. 4, the opening 88 may have a general oval configuration having a radial length Bi and a transverse length Ti. In the illustrated embodiment, the transverse length Ti is greater than the radial length Bi. In a preferred embodiment, the transverse length Ti is within a range of about 30 millimeters to about 54 millimeters. In a more preferred embodiment, the transverse length Ti is within a range of about 37 millimeters to about 47 millimeters. In a preferred embodiment, the radial length Bi is within a range of about 14 millimeters to about 34 millimeters. In a more preferred embodiment, the radial length Bi is within a range of about 19 millimeters to about 29 millimeters. The opening 88 may be positioned at any suitable location within the inner web 24. In the illustrated embodiment, the opening 88 is spaced from the wheel axis X by a radius Ri. In a preferred embodiment, the radius Ri is within a range of about 50 millimeters to about 110 millimeters. In a more preferred embodiment, the radius Ri is within a range of about 74 millimeters to about 84 millimeters.

[0057] Referring to Fig. 3, the outer web 25 generally connects, secures, or otherwise joins the distal end 50 of a spoke 22 to the outer rim 14. In the illustrated embodiment, the outer web 25 generally extends from the inboard rear side 58 of the spokes 22 to the central wall 19 of the outer rim 14. As best shown in Fig. 7, the outer web 25 does not extend from the outboard front side 56, thereby providing the gap G between the outermost end 62a of the prong 62 and the central wall 19 of the outer rim 14. Thus, the distal ends 50 of the spokes 22 are radially inwardly spaced from the outer rim 14. However, the distal ends 50 of the spokes 22 are indirectly connected to the outer rim 14 via the outer web 25 extending from the inboard rear side 58 of the spokes 22 to the central wall 19 of the outer rim 14. In a preferred embodiment, the gap G is within a range of about 10 millimeters to about 40 millimeters. In a more preferred embodiment, the gap G is within a range of about 20 millimeters to about 30 millimeters. Of course, the wheel disc 12 could be designed without a gap G such that distal ends 50 of the spokes extend all the way to central wall 19 of the rim 14, and wherein Dw would then extend upward, as viewing Fig.

7.

[0058] The structural details of the outer web 25 will now be described with respect to Fig. 3. The outer web 25 includes first and second outer wings 90 and 92. The first and second outer wings 90 and 92 extend circumferentially outwardly from the first and second prongs 60 and 62, respectively. The outer web 25 further includes first and second inner wings 94 and 96. The first and second inner wings 94 and 96 extend circumferentially inwardly toward one another from the first and second prongs 90 and 92, respectively. In the illustrated embodiment, the first and second outer wings 90 and 92 and the first and second inner wings 94 and 96 are connected together to form an arcuate shaped continuous connection portion 98 connecting the distal ends 50 of the spokes 22 with the central wall 19 of the outer rim 14. As shown in Fig. 4, the connection portion 98 is formed within an angle C of about 40 degrees. Of course, the connection portion 98 may have any suitable angle or length. Alternatively, the connection portion 98 need not be continuous but may include breaks, openings, or notches formed therein. In a preferred embodiment, the angle C is within a range of about 20 degrees to about 70 degrees. In a more preferred embodiment, the angle C is within a range of about 30 degrees to about 50 degrees.

[0059] As shown in Fig. 7, the outer web 25 is connected to the central wall 19 of the outer rim 14 by a relatively narrow band defined by the connection portion 98. The depth of the integral connection portion 98 is represented by the depth Dw. It should be understood that the depth Dw may be relatively narrow, as shown in the illustrated embodiment of the wheel 10, or may be larger and/or having a jagged or non-continuous shape. Thus, the connection portion 98 may have any suitable shape or size. In a preferred embodiment, the depth Dw is within a range of about 4 millimeters to about 20 millimeters. In a more preferred embodiment, the depth Dw is within a range of about 8 millimeters to about 16 millimeters.

[0060] In a preferred embodiment, the distal end 50 of the spokes 22 and respective first and second inner wings 94 and 96 define an opening 100 between the first and second prongs 60 and 62. The opening 100 reduces mass of the wheel 10 and may provide ventilation. The opening 100 can have any size or shape. As shown in Fig. 4, the opening 100 has a radial length B2, and a transverse length T2. In a preferred embodiment, the transverse length T2 is within a range of about 20 millimeters to about 60 millimeters. In a more preferred embodiment, the transverse length T2 is within a range of about 38 millimeters to about 48 millimeters. In a preferred embodiment, the radial length B2 is within a range of about 40 millimeters to about 120 millimeters. In a more preferred embodiment, the radial length B2 is within a range of about 70 millimeters to about 90 millimeters. Alternatively, multiple openings may be formed between the prongs 60 and 62 instead of having a single opening 100. In yet another alternative, the first and second wings 94 and 96 may form a single web extending between the first and second prongs 60 and 62 and the central wall 19 of the outer rim 14.

[0061] The opening 100 may be positioned at any suitable location between he first and second prongs 60 and 62. In the illustrated embodiment, the opening 100 is spaced from the wheel axis X by a radius R2. In a preferred embodiment, the radius R2 is within a range of about 70 millimeters to about 160 millimeters. In a more preferred embodiment, the radius R2 is within a range of about 100 millimeters to about 130 millimeters.

[0062] The inner webs 24 and the outer webs 25 may be separate from one another or may be linked or connected by intermediate webs 110, as shown in the illustrated embodiment of the wheel 10. As best shown in Fig. 3, the inner webs 24 and outer webs 25 are connected by relatively thin or narrow intermediate webs 110 generally extending from the distal ends 50 of the spokes 22. The wheel disc 12 includes ten intermediate webs 110 corresponding to being connected to two sides of the five spokes 22. Similar to the inner and outer webs 24 and 25, the intermediate webs 110 extend from the inboard rear side 58 of the spokes 22. As shown in Fig. 3, the intermediate webs 110 may have a relatively small thickness B. In a preferred embodiment, the thickness B is within a range of about 1 millimeter to about 10 millimeters. In a more preferred embodiment, the thickness B is within a range of about 3 millimeters to about 5 millimeters.

[0063] As shown in Figs. 3 and 4, the inner webs 24, the outer webs 25, and the central wall 19 of the outer rim 14 define five relatively large vent openings 120. Of course, the wheel 10 can include any number of vent openings 120 or may be formed with no vent openings at all such that the inner and outer webs 24 and 25 form a continuous membrane between adjacent spokes 22. The vent openings 120 may have any suitable shape of size. As referenced in Fig. 4, the vent openings 120 may have a radial length B3 and a transverse length T3. In the illustrated embodiment, the transverse length T3 is slightly greater than the radial length B3. In a preferred embodiment, the transverse length T3 is within a range of about 60 millimeters to about 240 millimeters. In a more preferred embodiment, the transverse length T3 is within a range of about 120 millimeters to about 180 millimeters. In a preferred embodiment, the radial length B3 is within a range of about 40 millimeters to about 170 millimeters. In a more preferred embodiment, the radial length B3 is within a range of about 90 millimeters to about 120 millimeters. The vent openings 120 may be positioned at any suitable location. In the illustrated embodiment, the vent openings 120 are spaced from the wheel axis X by a radius R3. In a preferred embodiment, the radius R3 is within a range of about 80 millimeters to about 180 millimeters. In a more preferred embodiment, the radius R3 is within a range of about 110 millimeters to about 140 millimeters.

[0064] There is illustrated in Fig. 8 a second embodiment of a wheel, indicated generally at 130. The wheel 130 is a five spoke configuration and may be similar in structure and function as the wheel 10 described above. Similar to the wheel 10, the wheel 130 includes a wheel disc 132, an annular outer rim 134, a plurality of spokes 136, a plurality of inner webs 138, and a plurality of outer webs 140. However, one of the differences between the wheels 10 and 130 is that the inner webs 138 lack any openings formed therein such as the openings 88 formed in the inner webs 24 of the wheel 10.

[0065] Another difference between the wheels 10 and 130 is that the wheel 130 further includes a plurality of relatively narrow arcuate connecting webs 142 extending between and connecting outer wings 144 of adjacent outer webs 134. The inclusion of the arcuate connecting webs 140 provides a continuous circumferential web connection for the wheel disc 132 such that the entire circumference of the wheel disc 132 is connected to an inner central wall 146 of the outer rim 134. Additionally, the arcuate connecting webs 140 provide for a continuous web around each of the plurality of ventilation holes 148. Thus, the ventilation holes 148 are defined by a continuous web edge 150 that encircles the respective ventilation holes 148.

[0066] Another difference between the wheels 10 and 130 is that the outer webs 140 of the wheel disc 132 includes inner wings 160 which also extend radially inwardly and in between prongs 162 and 164 of the spokes 136. The configuration of the inner wings 160 form openings 166 therein such that a continuous web encircles each of the openings 166. Thus, the openings 166 are defined by a continuous web edge 168 that encircles the respective openings 166.

[0067] There is illustrated in Fig. 9 a third embodiment of a wheel, indicated generally at 180. The wheel 180 is a five spoke configuration and may be similar in structure and function as the wheel 10 described above. Similar to the wheel 10, the wheel 180 includes a wheel disc 182, an annular outer rim 184, a plurality of spokes 186 and a plurality of outer webs 190. However, one of the differences between the wheels 10 and 180 is that distal ends 192 of the spokes 186 extend radially outwardly and connect with a central wall 194 of the outer rim 184. The distal ends 192 of the spokes 186 include first and second prongs 196 and 198 having outermost ends 200 and 202, respectively, directly connected to the central wall 194 of the outer rim 184.

[0068] 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 150% can be obtained while reducing the weight by about 17% compared to conventionally known similar sized and similar material wheels. These advantages can be obtained by: the thin webs or membranes connecting adjacent spokes near the hub and/or rim junction, the variational spoke cross section by allocating structural mass strictly wherever necessary, the bifurcated spoke at the rim connection, and/or any combination thereof. 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).

[0069] 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.