Pivot bearing

Abstract

A pivot bearing used in a vehicle trailing arm suspension includes a housing, a resilient bush compressed and bonded in the housing, and a rigid axial sleeve in the bush. The bush has voids above and below the sleeve when the pivot bearing is fitted for use and stiffening elements which extend between the voids at opposite sides of the sleeve. When the pivot bearing is in use in a vehicle trailing arm suspension, the voids increase flexibility of the bush under generally vertical loading on the pivot bearing. The stiffening elements enhance the stiffness of the bush in generally horizontal direction for improved vehicle dynamics and reduced vibration. Preferably, the stiffening elements are of plate or leaf form, are bonded to the bush, and extend arcuately about the sleeve. The voids extend partially through the axial thickness of the bush from opposite ends of the bush and generally accurately about the sleeve. The bush also has enlarged opposite circumferential end portions. The end portions extend circumferentially beyond diametrically opposite parts of the external circumference of the sleeve and are in-turned towards the sleeve. Edges of the stiffening elements extend into the opposite end portions of the voids.

1 - 43 . (canceled)  
   
   
       44 . A suspension trailing arm for heavy vehicles and trailers, the suspension trailing arm comprising: 
 a first end and a second end separated along a longitudinal axis;    a formation for attachment of an axle oriented along an axle axis substantially transverse to said longitudinal axis and remote from said first end of the suspension trailing arm; and    a pivot bearing, said first end of the suspension trailing arm including said pivot bearing for attaching the suspension trailing arm to a supporting part of a vehicle, said pivot bearing having an axis substantially parallel to said axle axis, said pivot bearing including: 
 a housing formed in said first end of the suspension trailing arm to attach the suspension trailing arm to said pivot bearing,  
 a resilient substantially cylindrical bush in said housing, said resilient substantially cylindrical bush including first portions having voids and second portions,  
 a rigid axial sleeve secured axially in said resilient substantially cylindrical bush, and said voids of said resilient substantially cylindrical bush are disposed above and below said rigid axial sleeve when said pivot bearing is fitted for use, and  
 stiffening elements of a material stiffer than a bush material of said resilient substantially cylindrical bush, wherein said stiffening elements are in said second portions of said resilient substantially cylindrical bush and extend between said first portions at opposing sides of said rigid axial sleeve.  
   
   
   
       45 . The suspension trailing arm according to  claim 44  wherein said stiffening elements are made of one of a metal and a plastic material.  
   
   
       46 . The suspension trailing arm according to  claim 44  wherein said stiffening elements are bonded to said resilient substantially cylindrical bush.  
   
   
       47 . The suspension trailing arm according to  claim 44  wherein said stiffening elements are of one of plate and leaf form.  
   
   
       48 . The suspension trailing arm according to  claim 44  wherein said stiffening elements extend arcuately in said second portions about said rigid axial sleeve.  
   
   
       49 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush has opposing ends, and said stiffening elements project from said opposing ends of said resilient substantially cylindrical bush.  
   
   
       50 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush is molded and said voids are formed in said resilient substantially cylindrical bush during molding.  
   
   
       51 . The suspension trailing arm according to  claim 44  wherein said voids extend at least generally arcuately in said first portions of said resilient substantially cylindrical bush about said rigid axial sleeve.  
   
   
       52 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush has an axial thickness and opposing ends, and said voids extend fully through said axial thickness of said resilient substantially cylindrical bush and extend into said resilient substantially cylindrical bush from said opposing ends.  
   
   
       53 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush has an axial thickness and opposing ends, and said voids extend partially through said axial thickness of said resilient substantially cylindrical bush and extend into said resilient substantially cylindrical bush from said opposing ends.  
   
   
       54 . The suspension trailing arm according to  claim 53  wherein said voids include two similar, directly opposed voids which extend towards one another from said opposing ends of said resilient substantially cylindrical bush, and said two similar, directly opposed voids are separated by a central solid region of said resilient substantially cylindrical bush.  
   
   
       55 . The suspension trailing arm according to  claim 44  wherein one of said voids is above said rigid axial sleeve and another of said voids is below said rigid axial sleeve, and each of said voids are elongated with respect to an external circumference of said rigid axial sleeve and extend for a distance about said rigid axial sleeve that is longer than an external diameter of said rigid axial sleeve.  
   
   
       56 . The suspension trailing arm according to  claim 55  wherein each of said voids has opposing enlarged circumferential ends whereby stresses in said resilient substantially cylindrical bush at said opposing enlarged circumferential ends of said voids are reduced, and compression of said resilient substantially cylindrical bush under vertical loading on said pivot bearing during use is facilitated.  
   
   
       57 . The suspension trailing arm according to  claim 56  wherein said voids have a main body, and said opposing enlarged circumferential ends of said voids are enlarged into a plurality of projections extending from said main body of said voids.  
   
   
       58 . The suspension trailing arm according to  claim 55  wherein each of said voids has opposite circumferential ends, and said voids each taper generally triangularly towards said rigid axial sleeve.  
   
   
       59 . The suspension trailing arm according to  claim 55  wherein each of said voids has opposite circumferential ends, and said stiffening elements extend into said opposite circumferential ends of said voids.  
   
   
       60 . The suspension trailing arm according to  claim 57  wherein said stiffening elements extend into said opposing enlarged circumferential ends of said voids between adjacent projections of said opposing enlarged circumferential ends.  
   
   
       61 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush is bonded to said rigid axial sleeve.  
   
   
       62 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush has axially opposing ends and said rigid axial sleeve protrudes from said axially opposing ends of said resilient substantially cylindrical bush.  
   
   
       63 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush has an interference fit in said housing.  
   
   
       64 . The suspension trailing arm according to  claim 44  wherein said resilient substantially cylindrical bush is compressed into and bonded in said housing, and said voids of said resilient substantially cylindrical bush are substantially closed.  
   
   
       65 . The suspension trailing arm according to  claim 44  wherein a pivot pin is located in said rigid axial sleeve and is supported by opposed limbs of a mounting which straddles said pivot bearing and fixes to the supporting part of the vehicle for use of the suspension trailing arm.  
   
   
       66 . The suspension trailing arm according to  claim 65  wherein ends of said rigid axial sleeve abut on thrust washers which abut opposed inner surfaces of respective limbs of said mounting.