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 vehicle 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. When the stiffness and rigidity of the wheel are reduced, performance of the wheel may be compromised. Thus, it would be desirable to remove mass from the wheel without a significant reduction in stiffness and rigidity. SUMMARY OF THE INVENTION

[0004] The present invention relates to an improved vehicle 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 which includes a hub defining a wheel axis. The hub includes a front face and a rear face opposite the front face. The wheel disc further including a plurality of spokes radially extending outwardly from the hub. A connecting portion on at least one spoke of the plurality of spokes joins a proximal end of the at least one spoke to the hub. The connecting portion includes a nose portion that extends over a portion of the front face of the hub.

[0006] According to this embodiment, the hub has a generally circular disc shape defining an outer circumferential edge, wherein the connecting portion of the at least one spoke joins the hub at the circumferential edge, and wherein the nose portion extends radially inwardly from the circumferential edge and over the portion of the front face of the hub.

[0007] According to this embodiment, the nose portion has a radial width which is less than a radial width of the at least one spoke.

[0008] According to this embodiment, the radial width of the nose portion is less than half the radial width of the spoke. [0009] According to this embodiment, the hub includes a generally circular front face and a generally circular rear face planar to one another defining a thickness therebetween.

[0010] According to this embodiment, a plurality of circumferentially spaced hub pockets is formed in the rear face of the hub.

[0011] According to this embodiment, the hub pockets are non-through holes such that each of the hub pockets defines a bottom surface formed in the hub.

[0012] According to this embodiment, each of the plurality of spokes includes a nose portion that extends over a portion of the front face of the hub.

[0013] According to this embodiment, each one of the plurality of hub pockets formed in the rear surface of the hub is located adjacent a corresponding nose portion formed on the front face of the hub.

[0014] According to this embodiment, a plurality of circumferentially spaced lug bolt receiving holes are formed in the front face of the hub, and wherein a plurality of hub pockets are formed in the rear face of the hub.

[0015] According to this embodiment, at least one of the plurality of hub pockets is interspaced between two lug bolt receiving holes.

[0016] According to this embodiment, the wheel disc further includes at least one bridge spanning between adjacent spokes of the plurality of spokes. [0017] According to this embodiment, the bridge has a generally constant cross-sectional shape along the length of the bridge.

[0018] According to this embodiment, the cross-sectional shape is generally rectangular.

[0019] According to this embodiment, the wheel disc includes a plurality of bridges such that a single bridge extends and spans between each adjacent pair of spokes.

[0020] According to this embodiment, each of the bridges defines a front face which are co-planar with one another.

[0021] According to this embodiment, the bridge defines a length between adjacent spokes of the plurality of spokes, and wherein the length is one of having a relatively linear shape, a convex shape, or concave shape.

[0022] According to this embodiment, the wheel disc is configured to be secured to a wheel rim by producing the wheel rim and the wheel disc by a casting 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 wheel rim of the fabricated vehicle wheel are formed of similar or dissimilar materials.

[0023] According to this embodiment, each of the spokes has a cross- sectional width which varies along the radially extending length of the spoke. [0024] According to this embodiment, each of the spokes has a central width spaced from the hub which bellows outwardly such that the central width is larger than the width of the spoke adjacent the hub.

[0025] According to another embodiment of the invention, a vehicle wheel disc may comprise, individually and/or in combination, one or more of the following features, elements, or advantages: an outer annular rim defining a wheel axis and adapted to receive a tire. The vehicle wheel further including a wheel disc having a circular shaped hub defining an outer circumferential edge, a front face and a rear face opposite the front face. The wheel disc further includes a plurality of spokes radially extending outwardly from the hub. Each of the spokes includes a connecting portion joining a proximal end of the corresponding spoke to the circumferential edge of the hub such that the plurality of spokes are circumferentially spaced around the hub. The connecting portions of each of the plurality of spokes includes a nose portion that extends over a portion of the front face of the hub and extends radially inwardly from the circumferential edge of the hub. The wheel disc further includes a plurality of bridges such that each bridge extends and spans between an adjacent pair of spokes.

[0026] According to this embodiment, each of the bridges are positioned closer to the hub in a radial direction than to the outer annular rim.

[0027] According to this embodiment, a plurality of circumferentially spaced lug bolt receiving holes are formed in the front face of the hub, and wherein a plurality of hub pockets are formed in the rear face of the hub. [0028] According to this embodiment, each one of the plurality of hub pockets formed in the rear surface of the hub is located adjacent a corresponding nose portion formed on the front face of the hub.

[0029] According to this embodiment, the outer annular rim defines a frontal plane perpendicular to the wheel axis, and wherein each bridge includes a front face which is one of offset in front of the frontal plane, offset behind the frontal place, or co-planar with the frontal plane.

[0030] 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

[0031] Fig. 1 is a front perspective view of a first embodiment of a vehicle wheel in accordance with the present invention.

[0032] Fig. 2 is a rear perspective view of the vehicle wheel of Fig. 1.

[0033] Fig. 3 is a front elevational view of the front face of the vehicle wheel of Fig. 1.

[0034] Fig. 4 is a rear elevational view of the rear face of the vehicle wheel of Fig. 1.

[0035] Fig. 5 is a side elevational view of the vehicle wheel of Fig. 1. [0036] Fig. 6 is a cross-sectional perspective view of the vehicle wheel taken along lines 6-6 of Fig. 3.

[0037] Fig. 7 is a cross-sectional perspective view of the vehicle wheel taken along lines 7-7 of Fig. 3.

[0038] Fig. 8 is a front elevational view of the front face of a second embodiment of a vehicle wheel in accordance with the present invention.

[0039] Fig. 9 is a front elevational view of the front face of a third embodiment of a vehicle wheel in accordance with the present invention.

[0040] Fig. 10 is a front elevational view of the front face of a fourth embodiment of a vehicle wheel in accordance with the present invention.

[0041] Fig. 11 is a cross-sectional view taken through a portion of a bridge of a fifth embodiment of a vehicle wheel in accordance with the present invention.

[0042] Fig. 12 is a cross-sectional view taken through a portion of a bridge of a sixth embodiment of a vehicle wheel in accordance with the present invention.

[0043] Fig. 13 is a cross-sectional view taken through a portion of a bridge of a seventh embodiment of a vehicle wheel in accordance with the present invention. [0044] Fig. 14 is a cross-sectional view taken through a portion of a bridge of an eighth embodiment of a vehicle wheel in accordance with the present invention.

[0045] Fig. 15 is a front elevational view of the front face of a ninth embodiment of a vehicle wheel in accordance with the present invention.

[0046] Fig. 16 is a cross-sectional view of the vehicle wheel taken along lines 16-16 of Fig. 15.

[0047] Fig. 17 is a cross-sectional view of a tenth embodiment of a vehicle wheel in accordance with the present invention.

[0048] Fig. 18 is a cross-sectional view of an eleventh embodiment of a vehicle wheel in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Referring now to the drawings, there is illustrated in Figs. 1 through 5 a vehicle wheel, indicated generally at 10. The wheel 10 generally incudes an inner wheel disc, indicated generally at 12, and an outer annular 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.

[0050] In a preferred embodiment (and as illustrated herein), the wheel disc 12 and the 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 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.

[0051] The wheel 10 can be produced or cast from any suitable material. For example, the wheel 10 may be in 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.

[0052] 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 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.

[0053] The wheel disc 12 is generally comprised of a central hub 20, a plurality of spokes 22, and a plurality of bridges 24 that connect 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 bridges 24 are all formed together as a single cast. [0054] The hub 20 is generally defined as a relatively thin plate or disc having a circular shape defining an outer circumferential edge 25. The hub 20 defines a front face 26 (or front surface), as seen in Figs. 1, 3, 6, and 7, and a rear face 28 (or rear surface), as seen in Figs. 2 and 4. 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 and rear faces 26 and 28 of the hub 20 are preferably planar surfaces perpendicular to the wheel axis X. As shown in Fig. 6, the hub 20 has a general thickness tu generally defined as the distance between the front face 26 and rear face 28. Of course, in an alternate embodiment of the wheel 10, the hub 20 could be configured such that the front and rear faces 26 and 28 are not planar nor parallel with one another.

[0055] The hub 20 includes a centrally located pilot aperture or hub hole 27. The hub 20 may include a tubular portion 29 extending outwardly from the front face 26 adjacent the hub hole 27. The hub hole 27 and the tubular portion 29 extend along the wheel axis X, as best seen in Fig. 1. The hub hole 27 and the tubular portion 29 may accommodate a portion of the axle and/or receive a protective/decorative cap (not shown). As best shown in Fig. 6, the tubular portion 29 may include one or more grooves 29a formed therein such as, for example, accommodating the mounting of a cap.

[0056] A plurality of lug bolt receiving holes 30 are circumferentially spaced around the hub hole 27 and wheel axis X. In the illustrated embodiment, the hub 20 includes five lug bolt receiving holes 30, which are preferably provided in the hub 20 radially offset with a respective one of each of the spokes 22. Alternatively, the number and/or location of the lug bolt receiving holes 30 may be other than illustrated if so desired. The lug bolt receiving holes 30 receive the lug bolts for securing the vehicle wheel 10 with lug nuts on the axle of an associated vehicle.

[0057] As best shown in Figs. 3 and 6, the lug bolt receiving holes 30 are formed by a first bore 32 formed in the front face 26 of the hub 20, and a second bore 34 formed in the rear face 28 of the hub 20. It is noted that the first bore 32 has a larger diameter than the second bore 34. The first bore 32 only extends partially into the hub 20 to define a circular ledge 36 having a surface planar with the front face 26 of the hub 20. The ledge 36 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 36 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. The formation of the first bore 32 and the ledge 36 helps to remove a slight amount of material or mass from the wheel 20. Alternatively, the lug bolt receiving holes 30 may be formed as a single hole of 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 30 may be formed to any size, in a preferred embodiment the diameter D of the second bore 34 (see Fig. 4) is within the range of about 12 millimeters to about 20 millimeters.

[0058] It is noted that the diameter or radius R of the hub 20 is generally formed as small as possible given the requirement for receiving the lug bolt receiving holes 30. As shown in Fig. 3, the outer radial edges of the lug bolt receiving holes 30 are right at the circumferential edge 25 of the hub 20. If desired, portions of the first bore 32 may extend beyond the radius R of the hub 20 such that the corresponding ledge 36 is slightly truncated. In the illustrated embodiment, the radius R of the hub 20 is less than a third as small as the radius RR of the outer rim 14. In a preferred embodiment, the radius R is within the range of about 110 millimeters to about 230 millimeters. In a preferred embodiment, the radius RR is within the range of about 381 millimeters to about 610 millimeters.

[0059] As best shown in Figs. 2, 4 and 7, the rear face 28 of the hub 20 includes a plurality of hub pockets 40 formed therein to help reduce the thickness of the hub 20 thereat, thereby reducing the overall mass of the wheel 10. The hub pockets 40 are interspaced with the lug bolt receiving holes 30. As will be discussed in detail below, the hub pockets 40 are also provided at locations adjacent connecting portions of the spokes 22 such that the mass of the hub 20 may be reduced at this region while features of the connecting portions of the spokes 22 provide rigidity at this location. As illustrated, there are five of the hub pockets 40. Alternatively, the wheel disc 12 may have fewer or greater than five of the hub pockets 40. As non-limiting examples, the hub pockets 40 may not be between every pair of the lug bolt receiving holes 30 or more than one hub pocket 40 may be between a pair of the lug bolt receiving holes 30.

[0060] As shown in Fig. 7, the hub pockets 40 each preferably have a depth Dp which is less than the thickness tu of the hub 20 (referenced in Fig. 6).

Thus, the hub pockets 40 preferably do not extend all the way through the hub 20 from the rear face 28 to the front face 26. In other words, in a preferred embodiment, the hub pockets 40 are not through holes formed in the hub 20. Each of the hub pockets 40 defines a radially extending bottom surface 42. In a preferred embodiment, the thickness tn of the hub 20 may range from about 10 millimeters to about 40 millimeters. In a more preferred embodiment, the thickness tn of the hub 20 may range from about 15 millimeters to about 25 millimeters. Consequently, in a preferred embodiment, the depth Dp of the hub pockets 40 may range from about 5 millimeters to about 35 millimeters. In a more preferred embodiment, the depth Dp of the hub pockets 40 may range from about 8 millimeters to about 12 millimeters. Of course, it should be appreciated that each of the hub pockets 40 may have the same hub pocket depth Dp or, alternatively, one or more of the hub pockets 40 may have a different hub pocket depth Dp. Alternatively, the hub pockets 40 may be omitted from the wheel disc 12.

[0061] The hub pockets 40 can have any suitable shape. In a preferred embodiment, the hub pockets 40 are formed so as to remove a maximum of material or mass from the hub 20 while maintaining rigidity for the hub 20. Thus, as shown in Fig. 4, a radial outer wall 44 has a length Low which is larger in length compared to length Liw of a radial inner wall 46. The hub pockets 40 may have side walls 48 that are curved to accommodate the curvature of the first bore 32 of the lug bolt receiving holes 30 formed in opposite front face 26 of the hub 20. This shape of the hub pocket 40 helps in maximizing the absence of material within the hub 20 while maintaining rigidity for the hub 20.

[0062] In a preferred embodiment, the length Low of the outer wall 44 may range from about 38 millimeters to about 54 millimeters. In a more preferred embodiment, the length Low of the outer wall 44 may range from about 42 millimeters to about 50 millimeters. Consequently, in a preferred embodiment, the length Liw of the inner wall 46 may range from about 27 millimeters to about 39 millimeters. In a more preferred embodiment, the length Liw of the inner wall 46 may range from about 30 millimeters to about 36 millimeters.

[0063] In the illustrated embodiment, the wheel disc 12 includes five of such 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 suitable means and the outer rim 14 may be formed integral but separate from the hub 20 and joined thereto by a suitable method.

[0064] Referring to Figs. 1 and 2, each of the spokes 22 generally includes a distal end 50 which connect, secure, or otherwise join the spokes 22 to the outer rim 14. Each of the spokes 22 also generally includes a proximal end 52 which connect, secure, or otherwise join the spokes 22 to the hub 20. The spokes 22 can have any shape radially extending from the hub 20 to the outer rim 14. Each of the spokes 22 may have an identical shape. Alternatively, one or more the spokes 22 may have differing shapes dependent of the placement about the hub 20.

[0065] 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 front face or inboard side of the wheel 10.

[0066] To demonstrate the differing widths of portions of the spokes 22 along the radial length, there is illustrated in Fig.4, four widths Wi, W2, W3, and W4 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 adjacent the connection point to the hub 20 and has the narrowest width compared to the other widths W2, W3, and W4. The spoke 22 generally bellows slightly outwardly in a radial direction from the proximal end 52 towards a connection of a bridge 24, as shown at width W2. Thus, the width W2 is greater than the width Wi.

[0067] In a similar manner, the spoke 22 generally bellows outwardly from a connection of a bridge 24 at a width W3 towards the distal end 50 to a width W4. Thus, the width W4 is greater than the width W3. 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, W3, and W4 are within a range of about 30 millimeters to about 60 millimeters. In a more preferred embodiment, the widths Wi, W2, W3, and W4 are within a range of about 35 millimeters to about 55 millimeters. It is also noted that an end portion 58 (see Figs. 3 and 4) at the distal end 50 of each spoke 22 may curve inwardly at the connection point to the outer rim 14.

[0068] A stated above, the spokes 22 can have any suitable shape and need not have a constant cross-sectional shape. As shown in Fig. 6, the spokes 22 can have varying axial thicknesses. As such there is illustrated in Fig. 6 two axial thicknesses ti and t2 taken along various locations along the length of one of the spokes 22. The thickness ti is generally taken at the region of the spoke 22 which connects with a corresponding bridge 24. The thickness t2 is generally taken towards the distal end 50 of the spoke 22. In a preferred embodiment, the thickness t2 at the distal end 50 can be reduced relative to the thickness ti to reduce the mass of the wheel disc 12. The thickness ti is about double the thickness of t2. In a preferred embodiment, the thickness ti is within the range of about 30 millimeters to about 50 millimeters. In a preferred embodiment, the thickness t2 is within the range of about 15 millimeters to about 30 millimeters.

[0069] As best shown in Figs. 1, 3, 6, and 7, the front face of each of the spokes 22 includes a connecting portion 60 at the proximal end 52 that generally connects with the circumferential edge 25 of the hub 20. The connecting portion 60 further includes a nose portion 64 that extends onto and above the front face 26 of the hub 20. The nose portion 64 is positioned at a distance radially inwardly from the circumferential edge 25 of the hub 20. As best shown in Fig. 3, a tip 66 of the nose portion 64 is spaced radially inwardly from the circumferential edge 25 by a distance Y. The tip 66 is located at the most radially inward portion of the nose portion 64 on the front face 26 of the hub 20.

[0070] As further shown in Fig. 3, the hub 20 has a radius R which is within the range of about 3 to 4 times the distance Y. In the illustrated embodiment, the distance Y is about 1/7 of the diameter (2 x R) of the hub 20. Thus, the nose portion 64 extends a relatively substantial distance onto the front face 26 of the hub. In a preferred embodiment, the radius R is within the range of about 60 millimeters to about 135 millimeters. In a more preferred embodiment, the radius R is within the range of about 70 millimeters to about 115 millimeters. In a preferred embodiment, the distance Y is within the range of about 17 millimeters to about 38 millimeters. In a more preferred embodiment, the distance Y is within the range of about 20 millimeters to about 32 millimeters.

[0071] Referring to Figs. 1, 6 and 7, it can be seen that each of the nose portions 64 of the connecting portions 60 of the spokes 22 extends axially above the front face 26 of the hub 20. In the illustrated embodiment, the nose portions 64 are curved in the radial direction such that the nose portions 64 increase in height or thickness along their radial outward path extending along the length of the spoke 22. This increase in height of the nose portions 64 occurs from their respective tips 66 to a corresponding apex 68. As shown in Fig. 3, the apex 68 of each nose portion 64 is located radially distant beyond the radius R of the circumferential edge 25 of the hub 20 in a preferred embodiment of the wheel 10.

[0072] It is also preferred that the nose portions 64 of the spokes 22 have a relatively narrow width WN (see Fig. 3) to further minimize the material and mass within the nose portions 64 while maintaining strength and rigidity at this region of the spoke 22 and the wheel disc 12. In the illustrated embodiment, the width WN is dimensionally less than half of the narrowest width portions Wi, W2, W3, and W4 (see Fig. 4) of the corresponding spoke 22. In a preferred embodiment, the width WN is within the range of about 8 millimeters to about 22 millimeters. In a more preferred embodiment, the width WN is within the range of about 12 millimeters to about 20 millimeters. As stated above, it should be appreciated that the nose portions 64 can have any suitable shape. As shown in Fig. 3, side walls 70 of the nose portions 64 may be slightly tapered in the axial direction to facilitate removal of the wheel 10 in the casting process.

[0073] As illustrated in Fig. 2 and the cross-sectional views of Figs. 6 and 7, the connecting portions 60 of the spokes 22 do not include nose portions on the rear face 28 of the hub 20 and instead curve slightly inwardly in the direction from the rear face 28 towards the front face 26. It has been found that nose portions are not necessary for rigidity purposes at these rear inboard regions of the wheel 10. The lack of protuberances or nose portions helps to provide a relatively high wheel offset to provide for clearance for an associated vehicle brake (not shown) positioned adjacent the rear face of the wheel 10.

[0074] It is noted that the hub pockets 40 formed in the rear face 28 of the hub 20 are located opposite, but adjacent or in line with, a corresponding nose portion 64 formed on the front face 26 of the hub 20. This positional relationship can be seen in the cross-sectional views of Figs. 6 and 7. This combination of hub pocket 40 and nose portion 64 helps minimize material and mass at this region of the hub 20 while providing sufficient rigidity for the connection of the spoke 22 to the hub 20.

[0075] As stated above, the wheel disc 12 preferably further includes a plurality of bridges 24 that connect adjacent spokes 22. The bridges 24 span between or otherwise connect adjacent spokes 22 of the plurality of spokes 22. As a non-limiting example, the bridges 24 provide additional rigidity between adjacent pairs of the spokes 22 and for the wheel 20. In the illustrated embodiment, there are five bridges 24 corresponding to the number of spokes 22. A single bridge 24 connects adjacent spokes 22. In an alternative embodiment, multiple bridges 24 may connect adjacent pairs of spokes 22.

[0076] In a preferred embodiment, a single bridge 24 spans adjacent spokes 22 and has a minimalist cross-sectional area to provide sufficient rigidity for the wheel disc 12 while minimizing the additional mass added to the wheel disc 12. As shown in Figs. 6 and 7, the bridges 24 have a generally rectangular cross-sectional shape with slightly tapered side walls 74 in the axial direction to facilitate removal of the wheel 10 in the casting process. The bridges 24 may have a generally constant thickness spanning between adjacent spokes 22. As shown in Fig. 6, the bridges 24 generally have a radial thickness tB. The bridges 24 further generally have an axial depth DB.

[0077] In a preferred embodiment, the thickness tB is within the range of about 8 millimeters to about 22 millimeters. In a more preferred embodiment, the thickness tB is within the range of about 12 millimeters to about 18 millimeters. In a preferred embodiment, the depth DB is within the range of about 30 millimeters to about 50 millimeters. In a more preferred embodiment, the depth DB is within the range of about 35 millimeters to about 45 millimeters.

[0078] It is noted that the radial thickness tB of the bridges 24 is much smaller than the width of any portion of the spokes 22, thereby helping to minimize the overall mass of the wheel disc 12. Although the bridges 24 are shown having a general constant thickness, the bridges 24 may have curved end portions 76 and 78 (see Fig. 6) that flare outwardly at end regions of the bridges 24 where connection with the spokes 22 occurs. Thus, instead of a sharp angle being formed between connecting bridges 24 and the spokes 22, a softer curved connection can be formed thereat.

[0079] To minimize the length, and therefore the mass of the bridges 24, the bridges 24 are preferably spaced at a relatively close radial distance from the circumferential edge 25 of the hub 20 while still maintaining suitable rigidity for the wheel disc 12. As shown in Fig. 3, the bridge 24 is spaced from the circumferential edge 25 of the hub at about a distance Z. In the illustrated embodiment, the distance Z is about less than half the radius R of the hub 20. In a preferred embodiment, the distance Z is within the range of about 15 millimeters to about 50 millimeters. In a more preferred embodiment, the distance Z is within the range of about 25 millimeters to about 35 millimeters.

[0080] The presence of the bridges 24 generally defines a plurality of windows or openings in the wheel disc 12 between the spokes 22. In the illustrated embodiment of Figs. 3 and 4, there are five relatively large openings 80 defined between distal ends 50 of adjacent spokes 22, a corresponding bridge 24, and a portion of the outer rim 14. There are five smaller openings 82 defined between the proximal ends 52 of the spokes 22, a corresponding bridge 24, and portion of the circumferential edge 25 of the hub 20. As shown in Figs. 3 and 4, the large openings 80 have a radial length A, while the smaller openings 82 have much smaller radial length B. Note that the dimension for the radial length B of the opening 82 may be equal to the dimension of the distance Z from which the bridge 24 is spaced from the circumferential edge 25 of the hub 20.

[0081] In the illustrated embodiment, the length A is about 2.5 times larger than the length B. In a preferred embodiment, the length A is within the range of about 60 millimeters to about 100 millimeters. In a more preferred embodiment, the length A is within the range of about 70 millimeters to about 90 millimeters. In a preferred embodiment, the length B is within the range of about 15 millimeters to about 50 millimeters. In a more preferred embodiment, the length B is within the range of about 25 millimeters to about 35 millimeters.

[0082] As best shown in Figs. 1 and 3, each of the bridges 24 have front facing surfaces 90 that are generally planar with one another and essentially lie in a single plane. Additionally, each of the spokes 22 includes front facing surfaces 92 that are co-planar with the surfaces 90 of the bridges 24 which give a pleasing aesthetic look to the wheel 10. The plane in which the surfaces 90 and 92 lie in is perpendicular to the wheel axis X and is spaced axially forward from the front face 26 of the hub 20. It should be understood that the surfaces 90 and 92 may have a slight curvature instead of being completely planar and/or that the front facing surfaces 92 may not be co-planar with the front facing surfaces 90.

[0083] It should be appreciated that the wheel 10 may be cast such that afterwards any portion of the wheel 10 can have material or structure machined away to vary the dimensions and overall mass of the wheel 10. Thus, any limitations of the casting can be compensated for by added material thickness during the casting. The added material thickness can later be machined off to form one or more of the components of the wheel 10 descried and shown herein.

[0084] There is illustrated in Fig. 8 a second embodiment of a vehicle wheel, indicated generally at 100. The wheel 100 is similar in structure and function as the wheel 10 described above with respect to Figs. 1 through 7. For example, the wheel 100 includes an inner wheel disc, indicated generally at 102 which may be similar, yet different, from the wheel disc 12 of the wheel 10 described above. The wheel 100 also includes an outer annular rim 104 which may be similar to the outer annular rim 14 of the wheel 10 described above. Similar to the wheel 10, the wheel 100 is preferably 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 100. Of course, the wheel disc 102 and rim 104 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 100.

[0085] The wheel disc 102 of the wheel 100 is generally comprised of a central hub 110, a plurality of spokes 112, and a plurality of bridges 114 that connect adjacent spokes 112 in a similar manner as described above with respect to the wheel 10. The central hub 110 of the wheel 100 may have a similar shape as the central hub 20 of the wheel 10. For example, the central hub 110 may be formed with a five bolt hole pattern in a similar manner as the central hub 20 of the wheel 10. It should be noted that although the wheel disc 102 of the wheel 100 includes five spokes 112 and five bridges 114, the wheel disc 102 may be formed with any number of spokes 112 and bridges 114.

[0086] One of the differences between the wheels 10 and 100 is that the wheel disc 102 of the wheel 100 is formed such that the bridges 114 are spaced at a greater radial distance from an axis X2 of the wheel 100. Thus, the bridges 114 are attached to corresponding spokes 112 at a radial distance which is greater compared to that of the wheel 10, as is best shown when comparing the wheel 102 of Fig. 8 relative to wheel 10 of Fig. 3. The presence of the bridges 114 generally defines a plurality of windows or openings in the wheel disc 102 between the spokes 112. In the illustrated embodiment of Fig. 8, there are five outer openings 120 defined between distal ends 122 of adjacent spokes 112, a corresponding bridge 114, and a portion of the outer rim 104. There are five inner openings 124 defined between proximal ends 126 of the spokes 112, a corresponding bridge 114, and portion of a circumferential edge 128 of the hub 110.

[0087] As shown in Fig. 8, the outer openings 120 have a radial length A2, while the inner openings 124 have a radial length B2. It is noted that unlike the wheel 10, the difference in sizes of the openings 120 and 124 of the wheel 100 is not as great compared to the openings 80 and 82 of the wheel 10. Although the increase in length of the bridges 114 may increase the mass compared to the mass of the bridges 24 of the wheel 10, the radially outwardly position of the bridges 114 may increase the rigidity of the wheel 100. In the illustrated embodiment, the length B2 is just slightly smaller than the length A2. In a preferred embodiment, the length A2 is within the range of about 50 millimeters to about 110 millimeters. In a more preferred embodiment, the length A2 is within the range of about 60 millimeters to about 80 millimeters. In a preferred embodiment, the length B2 is within the range of about 25 millimeters to about 55 millimeters. In a more preferred embodiment, the length B2 is within the range of about 35 millimeters to about 45 millimeters.

[0088] There is illustrated in Fig. 9 a third embodiment of a vehicle wheel, indicated generally at 130. The wheel 130 is similar in structure and function as the wheels 10 and 100 described above. For example, the wheel 130 includes an inner wheel disc, indicated generally at 132 and an outer annular rim 134 which may be similar to the outer annular rims 14 and 114 of the wheels 10 and 100, respectively. Similar to the wheels 10 and 100, the wheel 130 is preferably 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 130. Of course, the wheel disc 132 and rim 134 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 130.

[0089] The wheel disc 132 of the wheel 130 is generally comprised of a central hub 140, a plurality of spokes 142, and a plurality of bridges 144 that connect adjacent spokes 142 in a similar manner as described above with respect to the wheels 10 and 100. The central hub 140 of the wheel 130 may have a similar shape as the central hubs 20 and 110 of the wheels 10 and 100, respectively. For example, the central hub 140 may be formed with a five bolt hole pattern. It should be noted that although the wheel disc 132 of the wheel 130 includes five spokes 142 and five bridges 144, the wheel disc 132 may be formed with any number of spokes 142 and bridges 144.

[0090] One of the differences between the wheel 130 and the wheels 10 and 100, is that the bridges 144 of the wheel disc 132 have a more exaggerated convex shape compared to the shape of the bridges 24 and 114 of the wheels 10 and 100. It is noted that although the illustrated embodiments of the bridges 24 and 114 of the wheels 10 and 100 have a slight convex curved shape, the shape of the bridges 24, 114, and 144 may be linear or have any suitable curvature. As shown in Fig. 9, the bridges 144 have a central portion 150 that is spaced at a greater radial distance from a wheel axis X3 compared to end portions 152 of the bridges 144 at attachment points to respective spokes 142. The curvature of the bridges 144 between the end portions 152 and along the central portions 150 define a convex curved shape of each of the bridges 144.

[0091] The convex shape of the bridges 144 alters the shape of the plurality of windows or openings formed in the wheel 130 as compared to the other wheels 10 and 100 illustrated herein. In the illustrated embodiment of Fig 9, there are five outer openings 160 defined between distal ends 162 of adjacent spokes 142, a corresponding bridge 144, and a portion of the outer rim 134. There are five inner openings 164 defined between proximal ends 166 of the spokes 142, a corresponding bridge 144, and portion of a circumferential edge 168 of the hub 140.

[0092] Compared to the other wheels 10 and 100, the outer openings 160 have a more arcuate shape such that a radial length A3 is more constant between outer edges 170 of the bridges 144 and inner edges 172 of the outer rim 134. Due the convex shaped nature of the bridges 144, the inner openings 164 have a more bulbous shape compared to the openings 82 and 124 of the wheels 10 and 100 due to the larger radial length B3. In a preferred embodiment, the length A3 is within the range of about 50 millimeters to about 110 millimeters. In a more preferred embodiment, the length A3 is within the range of about 60 millimeters to about 80 millimeters. In a preferred embodiment, the length B3 is within the range of about 25 millimeters to about 55 millimeters. In a more preferred embodiment, the length B3 is within the range of about 35 millimeters to about 45 millimeters.

[0093] There is illustrated in Fig. 10 a fourth embodiment of a vehicle wheel, indicated generally at 180. The wheel 180 may be similar in structure and function as the wheels 10, 100 and 130 described above. One of the differences is that the wheel 180 includes bridges 182 having a concave shape instead of the convex shape of the wheel 130. As shown in Fig. 10, the bridges 182 have a central portion 184 that is spaced at a closer radial distance from a wheel axis X4 compared to end portions 186 of the bridges 182 at attachment points to respective spokes 190. The curvature of the bridges 182 between the end portions 186 and along the central portions 184 define a concave curved shape of each of the bridges 182.

[0094] The concave shape of the bridges 182 alters the shape of the plurality of windows or openings formed in the wheel 180 as compared to the other wheels 10, 100, and 130 illustrated herein. In the illustrated embodiment of Fig 9, there are five outer openings 192 defined between distal ends 194 of adjacent spokes 190, a corresponding bridge 182, and a portion of and outer rim 195. There are five inner openings 196 defined between proximal ends 198 of the spokes 142, a corresponding bridge 182, and portion of a hub 199. Compared to the other wheels 10 and 100, the outer openings 192 are much larger and have a relatively large radial length A4. Due the concave shaped nature of the bridges 182, the inner openings 196 have a relatively small radial length B4.

[0095] In a preferred embodiment, the length A4 is within the range of about 80 millimeters to about 120 millimeters. In a more preferred embodiment, the length A4 is within the range of about 90 millimeters to about 110 millimeters. In a preferred embodiment, the length B4 is within the range of about 5 millimeters to about 35 millimeters. In a more preferred embodiment, the length B4 is within the range of about 15 millimeters to about 25 millimeters.

[0096] As shown in Fig. 10, the cross-sectional shape or thickness of the bridges 182 need not be constant. For example, the central portions 184 of the bridges 182 may have a thickness tBi which is greater than the thickness tB2 of the end portions 186. In a preferred embodiment, the length tBi is within the range of about 9 millimeters to about 21 millimeters. In a more preferred embodiment, the length tBi is within the range of about 12 millimeters to about 18 millimeters. In a preferred embodiment, the length tB2 is within the range of about 6 millimeters to about 18 millimeters. In a more preferred embodiment, the length tB2 is within the range of about 9 millimeters to about 15 millimeters.

[0097] As stated above, the cross-sectional shape and size of the bridges can be any suitable shape and can have any suitable dimensions. There is illustrated in Figs. 11 through 14, examples of alternate embodiments of crosssections of bridges which may be used in any of the wheels described herein. For example, there is illustrated in Fig. 11 an embodiment of a bridge 200 having a thickness tBA and a depth of DBA. The bridge 200 generally illustrates that the thickness and the depth of the bridge 200 may have generally equal dimensions forming a general square shaped cross-section. Of course, the dimensions of the thickness tBB and the depth DBB need not be exactly equal.

[0098] Fig. 12 illustrates a bridge 202 having a thickness tBB and a depth DBB. Fig. 13 illustrates a bridge 204 having a thickness tsc and a depth DBC. The bridges 202 and 204 generally illustrate bridges having a generally rectangular cross-sectional shape wherein the dimensions of the thicknesses and the depths vary such that the bridge may be defined as narrow or wide. Fig. 14 illustrates a bridge 206 having a non-rectangular cross-sectional shape. The bridge 206 can have any suitable shape and may have more than four sides, such as is shown in Fig. 14. It is also noted that the sides of the bridges need not be flat or planar but may be curved or uneven such as the sides 210 and 212 illustrated in Fig. 14. [0099] There is illustrated in Figs. 15 and 16 a ninth embodiment of a vehicle wheel, indicated generally at 220. The wheel 220 is similar in structure and function as the wheels described above. For example, the wheel 220 includes an inner wheel disc, indicated generally at 222. The wheel 220 also includes an outer annular rim 224 which may be similar to the outer annular rims of the wheels described above. The wheel disc 222 of the wheel 220 is generally comprised of a central hub 230, a plurality of spokes 232, and a plurality of bridges 234 that connect adjacent spokes 232 in a similar manner as described above with respect to the other wheels. It should be noted that although the wheel disc 222 of the wheel 220 includes five spokes 232 and five bridges 234, the wheel disc 222 may be formed with any number of spokes 232 and bridges 234.

[00100] One of the differences of the wheel 220 compared to other wheel embodiments described herein is that the bridges 234 are formed in an uneven or asymmetrical shape. For example, the bridges 234 include central portions 240 that extend between end portions 242 which are connected to adjacent spokes 232. The bridges 234 define a front face 250. As best shown in Fig.

15, the front faces 250 at the central portions 240 are not symmetrical about the wheel axis X5. The dimensions of the front faces 250 fluctuate in an uneven manner extending from one end portion 242 to the other end portion 242.

Thus, it should be understood that any of the embodiments of wheels in accordance with this invention may have any desired shape or pattern and may even include an asymmetric cross-sectional shape.

[00101] As shown in the embodiment of the wheel 220 of Fig. 15, the bridges

234 are relatively close to the hub 230 in the radial direction, thereby forming and defining relatively large outer openings 260 and relatively small or narrow inner openings 262 relative to one another.

[00102] Referring to Fig. 16, a front circumferential edge 270 of the outer rim 224 defines a frontal plane 272 of the wheel 220. It should be understood that any portions of the front faces 250 of the bridges 234 may be co-planar with the frontal plane 270, offset behind the frontal plane 270, or offset in front of the frontal plane 270 as is shown in Fig. 16 with respect to the wheel 220. There is illustrated in Fig. 17 an example of a wheel 300 wherein at least a portion of a bridge 302 extends into a frontal plane 304 defined by a front circumferential edge 306 of an outer rim 308 of the wheel 300. It is also noted that a front face 310 of a bridge 302 is offset in front (leftward as viewing Fig. 17) of the frontal plane 304. There is illustrated in Fig. 18 an example of a wheel 320 wherein a front face 322 of a portion of a bridge 324 is offset behind a frontal plane 326 defined by a front circumferential edge 328 of an outer rim 330 of the wheel 320.

[00103] 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 28% can be obtained while reducing the weight by about 21% compared to conventionally known similar sized and similar material wheels. These advantages can be obtained by: optimizing the bridges between adjacent spokes, utilizing variable profiles of the spokes to allocate structural mass in key areas, utilizing nose portions of the spokes to increase the stiffness in the hub and spoke connection point, 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).

[00104] 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.