Motor vehicle wheel

A wheel for a motor vehicle has a wheel spider with spokes defining large air openings therebetween. The spokes extend approximately radially from the wheel hub to the wheel rim. Each spoke comprises at least two outer ribs that extend approximately parallel to one another. At least two inner ribs extend diagonally between the spokes. The inner ribs connect the outer ribs with one another and intersect each other.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to a wheel for a motor vehicle, and more particularly 
to a wheel having a plurality of spokes defining relatively large air 
openings therebetween, each of the spokes comprising of ribs extending 
essentially radially from the wheel hub to the wheel rim. 
This application claims the priority of German Patent Application No. 196 
12 115.9 filed on Mar. 27, 1996 in Germany, the disclosure of which is 
expressly incorporated by reference herein. 
A wheel for a motor vehicle is known from German Design Patent M 95 03 760, 
said wheel having spokes between air openings, said spokes each consisting 
of two outer ribs running radially and extending from the rim flange to 
the wheel hub, with a continuous elongate air opening provided between the 
outer ribs. 
A goal of the invention is to provide a wheel for a motor vehicle having a 
wheel spider which provides optimum air throughput and guarantees high 
strength. 
These and other goals have been achieved according to the present invention 
by providing a wheel for a motor vehicle including a wheel spider having a 
plurality of spokes extending radially between a wheel hub and a wheel 
rim, adjacent ones of the spokes and the wheel rim defining air openings 
therebetween, each of the spokes comprising: at least two outer ribs which 
extend approximately parallel to each other between the wheel hub and the 
wheel rim; and at least two inner ribs extending diagonally between the 
outer ribs, the inner ribs intersecting each other. 
These and other goals have also been achieved according to the present 
invention by providing a mold for a wheel for a motor vehicle, the mold 
comprising mold openings for receiving a material for forming the wheel, 
the mold openings defining a wheel hub, a wheel rim, and a plurality of 
spokes extending radially between the wheel hub and the wheel rim, the 
mold openings which define each of the spokes including mold openings 
which define: at least two outer ribs which extend approximately parallel 
to each other between the wheel hub and the wheel rim; and at least two 
inner ribs extending diagonally between the outer ribs, the inner ribs 
intersecting each other. 
One advantageous feature achieved by the present invention results from the 
construction of the wheel spider with a plurality of spokes that join to 
form a lattice-like composite structure for strength. For this purpose, 
inner ribs are provided which run diagonally between the outer ribs of 
each spoke, said inner ribs intersecting with one another. The inner ribs 
intersect each other in an area between the wheel center point and the 
wheel rim, for example between 30% and 70% of the radial distance between 
the wheel center point and the wheel rim, and more preferably between 50% 
and 70% of the radial distance between the wheel center point and the 
wheel rim. In one preferred embodiment, five spokes are provided, which 
achieves a particularly strong wheel structure. 
The filigree (i.e., lattice-like) design of the individual spokes with 
additional internal air openings in each spoke between the outer ribs and 
the internal ribs advantageously achieves a stable wheel with great 
strength, especially high torsional stiffness. This is accomplished in 
particular since the outer ribs of adjacent spokes which are directly 
opposite each other in a circumferential direction (i.e., the outer ribs 
of adjacent spokes which define one of the relatively large air openings 
in the wheel), as well as one diagonal inner rib of each spoke, meet at a 
node proxima a hole for a mounting bolt. In one preferred embodiment, four 
internal air openings are provided in each spoke, which achieves a 
particularly strong wheel structure. 
In addition to the relatively large air opening between the individual 
ribs, smaller air openings are provided within the spokes that are made 
roughly polygonal, e.g. triangular. The diagonal position of the inner 
ribs means that in each case two air openings of approximately the same 
size are located opposite one another with respect to the intersection 
point between the inner ribs. 
The relatively large air openings defined between adjacent spokes of the 
wheel are essentially triangular and have at their radially outer 
periphery with respect to the wheel hub an external curved shape 
determined by the wheel rim. The relatively large air openings are rounded 
at the vertices of the outer ribs of adjacent spokes, with these rounded 
areas being located opposite the holes for the mounting bolts, 
respectively.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring to FIGS. 1 and 2, wheel 1 comprises a plurality of spokes 3 in 
the configuration of a wheel spider 2. The spokes 3 extend generally 
radially between the wheel hub 20 and the wheel rim 22, and define large 
air openings 4 (first air openings) therebetween. Each spoke 3 consists 
essentially of two outer ribs 5, 6 located approximately parallel to one 
another, and inner ribs 7, 8 extending diagonally between the outer ribs. 
The inner ribs 7, 8 are arranged so that they intersect to form triangular 
air openings 9, 10, 11, and 12 (second air openings) between themselves 
and the outer ribs 5, 6. An intersection 13 of inner ribs 7, 8 is located 
between the wheel hub 20 and the wheel rim 22 at a radial distance D from 
the wheel center point C. In the illustrated embodiment, the distance D is 
approximately 60% of the distance between the wheel center point C and the 
wheel rim. However, the distance D may be appropriately varied and 
selected by a person of ordinary skill in the art based on individual 
design criteria. 
Extensions of the midlines of directly opposite outer ribs 5 and 6 of 
adjacent spokes 3 (i.e., the outer ribs 5 and 6 that enclose the large air 
openings 4 between them), as well as respective diagonally-extending inner 
ribs 8 and 7 of said adjacent spokes 3, meet approximately in the vicinity 
of the holes 14 for the wheel mounting bolts located between said adjacent 
spokes at the wheel hub 20, as shown in dot-dash lines in FIG. 1. 
Of the four smaller air openings 9, 10, 11, and 12 in each spoke 3, two air 
openings 9, 11 and 10, 12, respectively, are located opposite one another 
with respect to the intersection point 13 of the inner ribs 7, 8. These 
air openings are triangular in shape, with openings 9 and 11 having larger 
air throughputs than the other two air openings 10 and 12. 
Inner air opening 12 has a diamond-shaped peripheral boundary edge when 
viewed as a whole, with the area located between the wheel mounting bolt 
holes 14 having a closed recessed area 15 to increase strength at the 
wheel hub. Triangular air opening 12 is located adjacent to this area 15. 
The large air openings 4 between adjacent spokes 3 have an outer curve 16 
formed by the shape of the wheel rim, which curve 16 is abutted by outer 
ribs 5, 6 of adjacent spokes 3. The large air openings 4 are defined at 
vertices 17 of the outer ribs 5, 6 of adjacent spokes 3 by a rounded area 
18, which is immediately opposite the respective wheel mounting bolt hole 
14 located between said adjacent spokes 3. 
Although the invention has been described and illustrated in detail, it is 
to be clearly understood that the same is by way of illustration and 
example, and is not to be taken by way of limitation. The spirit and scope 
of the present invention are to be limited only by the terms of the 
appended claims.