Abstract:
A two piece fiber reinforced composite wheel includes a molded inner rim portion defining an outboard engagement surface and a molded outer rim portion defining an inboard engagement surface. The inner and outer rim portions are conformed so as to interlock together and are adhesively bonded. The inner and outer rim portions engage forming a plurality of spoke sections having substantially box shaped cross sections. The spoke sections are further connected with fasteners.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to automobile wheels, and more particularly to injection molded plastic composite automobile wheels. 
     BACKGROUND 
     The automotive industry has increasingly been motivated to provide automobiles with decreased mass. A general trend toward more fuel efficient vehicles has influenced automobile manufacturers to develop more economical, light weight vehicle components. In order to produce vehicles which are lighter and less expensive there has been a strong movement in the automotive industry to develop vehicle body components which have been molded from plastic. 
     The present invention recognizes that the cost of an automobile can be reduced by minimizing the weight of its wheels. The cost of a lightweight automobile is relatively low because, among other things, a lightweight automobile can be propelled by a relatively small fuel-efficient power plant. Additionally, certain lightweight materials happen to be inexpensive, and easy to manufacture. 
     Furthermore, the present invention recognizes that still further weight and cost savings would accrue from using plastic composite as the material for the wheels. More particularly, the reduced weight of plastic wheels may make it possible to incorporate a comparatively simplified, cost effective, lighter weight suspension system because of the less unsprung wheel mass. 
     Although plastic compostite wheels represent substantial benefits, they also present a common drawback of having decreased structural strength. More specifically the compression strength generally is reduced from conventional steel or alloy wheel rims. In order to overcome this problem, it is necessary to provide a reinforced plastic wheel capable of increased structural strength. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a two piece structural fiber reinforced composite wheel. 
     It is yet another object of the present invention to provide a lightweight automobile wheel that has radial spoke sections that have substantially box shaped cross sections. 
     A further object of the present invention is to provide a lightweight automobile wheel that meets wheel durability and serviceability requirements under heavy structural loading. 
     Still another object of the present invention is to provide a lightweight automobile wheel which is simple in structure, inexpensive to manufacture and refined in appearance. 
     These and other objects of the present invention are obtained by providing a lightweight automobile wheel which includes an outboard unitary composite wheel rim which defines an inboard oriented engagement surface. Additionally, the wheel includes an inboard unitary composite wheel rim that defines an outboard oriented engagement surface which is formed for mating with the inboard oriented engagement surface. 
     In the preferred embodiment, a plurality of fasteners are engaged with the rims within the spoke sections for holding the rims together. The rims are also held together by an adhesive. The inboard composite wheel rim and the outboard composite wheel rim engage such that the adhesive provides an air tight seal between the two rims making it suitable to accept a tire. The spoke sections join at a central disc-shaped portion having apertures suitably incorporated to engage a wheel hub member. Reinforcing wall portions are incorporated in the spoke sections for structural support. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of the outboard surface of the outboard unitary composite wheel rim constructed in accordance with the teachings of the preferred embodiment of the present invention. 
     FIG. 2 is a perspective view of the inboard surface of the outboard unitary composite wheel rim constructed in accordance with the teachings of the preferred embodiment of the present invention. 
     FIG. 3 is a perspective view of the outboard surface of the inboard unitary composite wheel rim constructed in accordance with the teachings of the preferred embodiment of the present invention. 
     FIG. 4 is a perspective view of the inboard surface of the inboard unitary composite wheel rim constructed in accordance with the teachings of the preferred embodiment of the present invention. 
     FIG. 5 is a perspective view of the inboard and outboard rim sections aligned prior to engagement. 
     FIG. 6 is a perspective view of the inboard and outboard rims operatively engaged. 
     FIG. 7 is a perspective view of a spoke section with a cutaway of the outboard unitary composite wheel rim for purposes of illustrating the interior spoke fastening members. 
     FIG. 8 is a cross sectional view of a spoke section taken along line  8 — 8  of FIG. 7 to illustrate a fastener interface in a spoke section. 
     FIG. 9 is a cross sectional view of a lug nut area taken along line  9 — 9  of FIG. 6 shown to illustrate wheel stud, rim, lugnut interface. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides a two piece composite wheel. With reference to the drawings, the two piece composite wheel constructed in accordance to the teachings of the present invention is illustrated and identified with reference numeral  10 . More specifically, the two piece composite wheel  10  includes an outboard composite rim  20  and an inboard composite rim  50 , as shown in FIG.  5 . The outboard composite rim  20  and inboard composite rim  50  are both molded of fiber reinforced plastic. One process for creating the fiber reinforced plastic includes injection molding or compression molding around a structural fiber material residing in the mold. The structural fiber material is preformed to encourage repeatable results and may include carbon, fiberglass, KEVLAR, nylon, mesh polymer or the like. The structural fiber material can also comprise a screen-like, woven material or a loose fiber configuration. 
     Referring now to FIGS. 1 and 2, a perspective view of the outboard face  25  of the outboard composite rim  20  is shown. The outboard composite rim  20  includes a plurality of radial outer spoke sections  27 . The outer spoke sections  27  connect to an outer hub portion  28  in the center of the outboard composite rim  20 . An indented reinforcement section  31  is integrated in the outer portion of the outer spoke sections  27  for structural enhancement. The inboard side of outer spoke sections  27  include outer wall extensions  29  located on each side of the outer spoke sections  27 , best shown in FIG.  2 . The outer hub portion  28  includes an aperture  33  defining the centerpoint of the outboard composite rim  20 . The outer hub portion  28  also includes a plurality of inset portions  32  with disk shaped end portions  34  defining an aperture  35  to receive a wheel stud (not shown). The disk shaped end portions  34  act as the mating surface for lug nuts (not shown). The outer spoke sections  27  extend radially outwardly from the outer hub portion  28  to circumferential wall portion  44 . Intermediate to the outer spoke sections  27 , flange sections  37  protrude inboard from the circumferential wall portion  44 . 
     FIG. 2 shows the inboard face  40  of the outboard composite rim  20 . The flange sections  37  include a plurality of support fins  42  offsetting the flange sections  37  at an inward angle of the circumferential wall portion  44 . The outer spoke sections  27  include inner wall sections  46  lying substantially perpendicular to the inboard face  40  of the outboard composite rim  20 . The inner surface of the outer spoke sections  27  include boss sections  39  adapted to receive fasteners  70  as shown and described herein with reference to FIG.  8 . The boss sections  39  are connected by inner wall sections  46  providing structural support. Ridge portions  48  extend between the outer wall extensions  29  of the outer spoke sections  27 . 
     FIG. 3 shows the outboard face  55  of the inboard composite rim  50 . The inboard composite rim  50  includes a plurality of radial inner spoke sections  57 . The inner spoke sections  57  are radially connected to an inner hub portion  58  in the center of the inboard composite rim  50  by an inwardly ramped section  59 . The inner hub portion  58  includes a plurality of outset portions  90  with disk shaped end portions  92  defining an aperture  94  to receive a wheel stud (not shown). The inner hub portion  58  includes an aperture  53  defining the centerpoint of the inboard composite rim  50 . 
     The inner spoke sections  57  are outwardly offset by wall extension portions  60  connecting the inner spoke sections  57  to a radial step portion  61  of the circumferential wall portion  62 . The wall extension portions  60  of the inner spoke sections  57  include a ramped step portion  65 . The face  67  of the ramped step portion  65  seats to the inboard face  40  of the circumferential wall portion  44  of the outboard composite rim  20  when the inboard composite rim  50  is mated with the outboard composite rim  20 . 
     The inner spoke sections  57  of the inboard composite rim  50  further include wall sections  72  that seat between the outer wall extensions  29  of the outer spoke sections  27  of the outboard composite rim  20  when the inboard composite rim  50  is mated with the outboard composite rim  20 . The inner spoke sections  57  further include reception portions  74  which receive the boss sections  39  of the outboard composite rim  20  and together accept a fastener  70  as shown in FIG. 8 for securing the outboard composite rim  20  to the inboard composite rim  50 . A wall portion  75  extends from the inboardmost reception portion  74  between the wall sections  72 . An outer flange  81  projects outward from the outer portion of the inner spoke sections  57 . Tab supports  82  extend in an outward direction from the wall extension portions  60 . 
     The mating surface is defined by and an adhesive is applied to the outside of wall sections  72 , up and around the wall portion  75  and around the inwardly ramped section  59 . The adhesive is further applied to the tab supports  82 , the reception portions  74  and the face  67  of the ramped step portion  65 . Bead extrusions  73  line the mating surface of the outboard face  55  of the inboard composite rim  50  to ensure the adhesive will not overflow as the inboard composite rim  50  and outboard composite rim  20  are mated. It is apparent however, that the bead extrusions  73  may be located along the mating surface of the inboard face  40  of the outboard composite rim  20 . 
     When the outboard composite rim  20  mates with the inboard composite rim  50 , the face  67  of the ramped step portion  65  of the inboard composite rim  50  mates to the outside of the flange sections  37  of the outboard composite rim  20 . Similarly, the tab supports  82  of the inboard composite rim  50  mate with the inner wall sections  46  of the outboard composite rim  20 . The wall sections  72 , outer flange portions  81 , wall portion  75  and reception portions  74  of the inboard composite rim  50  mate with the outer wall extensions  29 , ridge portions  48 , the inboard face  40  and the boss sections  39  of the outboard composite rim  20  respectively. Accordingly, the inner hub portion  58  of the inboard composite rim  50  mates with the outer hub portion  28  of the outboard composite rim  20 . An air tight fit results around the respective mating portions. 
     FIG. 4 shows the inboard face  77  of the inboard composite rim  50 . The inner spoke sections  57  of the inboard composite rim  50  include a plurality of inset portions  78  with disk shaped end portions  79  defining an aperture  80  to receive a fastener  70  as shown in FIG.  8 . 
     FIG. 5 illustrates the alignment of the inboard composite rim  50  and the outboard composite rim  20  prior to engagement. The spoke sections from the respective rims create box sections when joined. Specifically, the outer wall extensions  29  from the outboard composite rim  20  serve as the first parallel walls that lie substantially perpendicular to inner spoke sections  57  of the inboard composite rim  50  and outer spoke sections  27  of the outboard composite rim  20  which serve as the other parallel walls. FIG. 6 illustrates the inboard composite rim  50  engaged to the outboard composite rim  20 . The inner spoke sections  57  of the inboard composite rim  50  align with the outer spoke sections  27  of the outboard composite rim  20  and the outer wall extensions  29  of the outboard composite rim  20  to form substantially box shaped spoke sections. 
     FIG. 7 and 8 show the interface between inner spoke sections  57  of the inboard composite rim  50  and outer spoke sections  27  of the outboard composite rim  20 . The boss sections  39  of the outer spoke sections  27  of the outboard composite rim  20  are received into the reception portions  74  of the inner spoke sections  57  of the inboard composite rim  50 . 
     FIG. 9 shows a lug nut  85  engaged with a wheel stud  89  extending through an aperture  69  of the inboard composite rim  50  and an aperture  35  of the outboard composite rim  20  which connects the wheel  10  to a vehicle (not shown). 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.