Abstract:
A link assembly for connecting a stabilizer crank arm and a suspension arm in a vehicle suspension system. The link assembly includes a barrel-shaped spacer having dome-shaped opposite ends. The spacer body has an axial bore therethrough which receives a bolt or stud shaft. The spacer spaces the crank arm and suspension system arm. Grommets on opposite ends of the shaft resiliently hold the arms against the spacer.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to vehicle suspension systems. It relates particularly to a stabilizer bar connector link in a suspension system. 
     BACKGROUND OF THE INVENTION 
     Motor vehicles have long been provided with independent suspension systems to absorb road shocks and other vibrations and provide a smoother, more comfortable ride. In suspension systems of this type, a stabilizer bar is normally incorporated to increase the roll rigidity and improve the steering stability of the vehicle. Typically, the stabilizer bar is a torsion rod oriented transversely of the vehicle, with an integral crank arm provided at each end. The rod is rotatably supported from the vehicle body adjacent each crank arm, and each crank arm is coupled to a suspension arm by a connector link assembly. 
     When the vehicle is subject to forces which cause it to roll, the crank arms pivot relatively about the longitudinal axis of the rod. Torsion forces which are exerted through the crank arms urge the suspension arms of the vehicle back toward their normal position. This type of stabilizer bar acts in a manner such that when paired left and right wheels differ in level from each other due to a cornering maneuver, the vehicle body will be prevented from excessive rolling or leaning to either side by torsional resistance of the stabilizer bar. 
     The link assembly which connects the torsion bar crank arms to the vehicle body and the suspension arms generally falls into one of two broad categories, a bolt-type assembly or a stud-type assembly. In the bolt-type a suitably dimensioned bolt is used to connect the stabilizer bar to the vehicle suspension arm. Pliable bushings or grommets on the bolt engage the exterior surfaces of the stabilizer bar arms and the vehicle suspension arms. A pair of similarly shaped grommets engage the interior surfaces of the respective vehicle elements and are in engagement with a pair of inner washers which are maintained at a predetermined spaced distance by a cylindrical sleeve mounted on the shaft of the bolt. 
     The stud-type assembly is essentially the same as the bolt-type. However, it includes two threaded ends requiring the use of retainer nuts on both ends of the stud. 
     There have been marked improvements in suspension link assemblies during the past ten years. An example of such an improvement is shown in Schwartz et al. U.S. Pat. No. 5,551,722. However, the industry is constantly searching for simpler, more durable, less expensive components. This search applies to suspension links as well as other components. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved link assembly for a vehicle suspension system. 
     Another object is to provide a link assembly which is simpler and less expensive than existing link assemblies. 
     Still another object is to provide a link assembly which is easier to fabricate and install than existing link assemblies. 
     The foregoing and other objects are realized in a stabilizer link assembly comprising a bolt having a hexagon head at one end of a shaft and a threaded section at the other end. The assembly comprises but six other parts. First, a washer is inserted in an annular groove formed in the flat base of a dome-shaped grommet. The preassembled grommet and washer are then slipped over the threaded end of the bolt shaft and seated against the bolt head. Then, one crank arm of a stabilizer bar, which normally takes the form of a flat bar segment with a hole in it for the bolt, is slipped over the threaded end and seated against the dome end of the grommet. 
     At this point, a one piece spacer embodying features the invention is slipped over the threaded end of the bolt shaft. The spacer body is molded of elastomeric material, preferably polyurethane, in the shape of a drum having dome-shaped ends. The combination of material, shape and wall thickness makes the drum axially stiff, although the material itself is somewhat elastic. A generally cylindrical bore through spacer is slightly larger in diameter than the diameter of the bolt shaft. However, the bore has three short raised surfaces formed therein which create an interference with the shaft and hold the spacer in position during assembly. One dome-shaped end seats against the stabilizer bar segment. 
     After the spacer is in place, the vehicles&#39; suspension arm is connected to the assembly. The arm, which normally takes the form of a flat bar segment with a hole in it for the bolt, is slipped over the threaded end and seated against the other dome-shaped end on the spacer. 
     Next, another dome-shaped grommet is preassembled with a washer. The washer has a hexagon nut already fastened to it. The preassembled grommet, washer and nut are slipped over the threaded end of the bolt shaft and threaded against the suspension bar segment. The nut is threaded onto the bolt shaft threads until it reaches the end of the threads, where the nut is stopped. 
     Whereas the spacer is described as being axially stiff, the grommets are substantially more elastic. In this regard, they are molded of rubber or the like. They resiliently hold the arms against the spacer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the drawings, which: 
     FIG. 1 is a front elevational view of a portion of a vehicle suspension system, illustrating the use of a link assembly embodying features of the present invention; 
     FIG. 2 is an exploded view of the link assembly of FIG. 1, albeit removed from the suspension system, i.e., as sold and before incorporation into the system; 
     FIG. 3 is a side view of a grommet and washer sub-assembly for the link assembly; and 
     FIG. 4 is a perspective view of a spacer embodying features of the invention; 
     FIG. 5 is an end view of the spacer seen in FIG. 4; 
     FIG. 6 is a sectional view of the spacer taken along line  6 — 6  of FIG. 5; and 
     FIG. 7 is a side elevational view of a grommet, washer and bolt sub-assembly for the link assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, and particularly to FIG. 1 a portion of a vehicle suspension system is seen generally at  10 . The portion of the suspension system shown includes a stabilizer bar crank arm  15  and a suspension arm  16 , connected by a link assembly  20  embodying features of the present invention. 
     Referring now to FIG. 2, the link assembly  20  is shown in an exploded view before assembly into the suspension system  10 . The link assembly  20  includes a hexagon head bolt  25 , an inner washer  26 , an inner dome-shaped grommet  27 , a spacer  30 , an outer dome-shaped grommet  31 , an outer washer  32  and a hexagon nut  33 . 
     The bolt  25  includes a shaft  41  of predetermined length. The shaft  41  has a threaded end  43  and a hex-shaped head  42 . The bolt  25  is preferably fabricated of steel which is plated for corrosion resistance. The threaded end  43  has threads thereon which end on the shaft in a stop for the nut  33 . 
     The washer  26  is fabricated of plated steel or high-strength plastic. It has an aperture  46  formed through its center for receiving the threaded end  43  and shaft  41  of the bolt  25 . 
     Referring now to FIG. 3, the dome-shaped grommet  27  is fabricated of resilient material which is rubber or medium density polyurethane. It has an enlarged outer end  50 . An annular groove  51  for receiving the washer  26  is molded into the end  50 . The grommet  27  has a roughly semi-spherical inner end  52  which, as will hereinafter be discussed, engages one side of the stabilizer bar crank arm  15  when the system  10  is assembled. A cylindrical bore  53  is formed through the grommet for receiving the bolt  25 . The bore  53  contains several inwardly extending nibs (not shown) designed to provide a slight interference fit with the shaft  41 . 
     Referring now to FIGS. 4-6, the spacer  30  is molded of the urethane elastomer TEXIN 245 in the illustrated embodiment. It is molded in an elongated, barrel-shaped body  60  so as to have opposite dome-shaped ends  61  and  62  and a center section  63 . 
     As best seen in FIGS. 4 and 5, the spacer body  60  has a series of eight longitudinally extending channels  65  formed in its outer surface leaving eight ribs  66  between them. The ribs  66  serve to further stiffen the spacer axially while the channels  65  which define them reduce the amount of plastic needed to form the spacer and thus reduce its cost and weight. 
     A generally cylindrical bore  68  is formed longitudinally through the body  60 . The diameter of the cylindrical bore  68  is slightly greater than that of the rod  41  in the bolt  25 . Three short raised surfaces  69  are formed in the center of the bore  68 , as seen in FIGS. 5 and 6. 
     The grommet  31  is a mirror image version of the grommet  27 . In other words, it is identical in construction to the grommet  27  but faces in the opposite direction in the assembly  20 . The washer  32  is identical to the washer  26 . It is preassembled into an identical annular groove in the grommet  31 . 
     The hex-nut  33  is a conventional nut with an axially projecting inner flange  71 . The hex-shaped end  72  of the nut  33  is outside the flange  71 . The flange  71  is inserted into the washer  32  and up set to hold the two together. 
     The system  10  is assembled by first threading the bolt shaft  41  through a washer  26  and grommet  27  to form a sub-assembly  75 . This sub-assembly  75  is seen in FIG.  7 . The shaft  41  is then passed through an aperture in the stabilizer bar crank arm  15 . 
     Next, the spacer  30  is slipped over the shaft  41 . The shaft is then passed through an aperture in the suspension arm  16 . Then the grommet  31 , washer  32  and nut  33  sub-assembly  76  are assembled and the nut  33  is threaded on the shaft  41 . 
     The hex-nut  33  is turned onto the threaded section  43  of the bolt  25  until the assembly  20  components and the arms  15 , 16  are snugly, but not tightly, engaged. The nut  33  is stopped at the end of the threaded section  43 . The grommets  27  and  31  resiliently hold the arms  15  and  16  against the spacer  30 . The outside diameter of the spacer&#39;s barrel shaped body  60  is substantially greater than that of each of the grommets  27  and  31 , as seen in FIG.  1 . Nevertheless, its dome-shaped ends  61  and  62  permit angular movement of the arms  15  and  16 . The arms  15  and  16  are free to move angularly relative to the bolt  25  through angles of about 30°. 
     While a preferred embodiment of the invention has been described, it should be understood that the invention is not so limited, and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.