Vehicle air suspension

Abstract

The invention is an air suspension system on vehicle driven axle to maintain substantially constant pinion shaft angle in response to traction force reaction on axle and brake torque induced reaction on axle and in response to position of axle in jounce and rebound. The invention is based on four bar mechanism geometrically arranged to achieve substantially constant pinion shaft angle. The four bars are represented by 1) hanger bracket, 2) trailing arm, 3) link rod and 4) driven axle housing with its attachments. In one of the preferred embodiments, the trailing arm is pivotally connected to top portion of hanger bracket attached to frame rail. The middle portion of trailing arm is “spherically” connected to axle top. Rear portion of trailing arm is connected to frame rail by air spring and shock absorber. One end of said link rod is pivotally connected to lower portion of hanger bracket and other end is pivotally connected to lower portion of axle.

1 . A trailing arm air suspension assembly for bearing partial weight of vehicle comprising:
 a trailing arm featuring leading portion, middle portion and trailing portion;   the said leading portion of the said trailing arm is formed to be vertically resilient or non-resilient;   said trailing portion of the said trailing arm adapted to be connected to air spring and a shock absorber either directly or through an adaptor;   said middle portion of the said trailing arm adapted to mate with the parts that form a spherical joint;   a hanger bracket adapted to be rigidly connected to the vehicle frame rail and adapted to pivotally connect the front end of the trailing arm and one end of a link rod;   an axle adapted to connect parts which form the spherical joint and adapted to connect parts which interface the other end of the said link rod with the axle.   
     
     
         2 . A suspension of  claim 1  wherein the front end of the said trailing arm is pivotally connected to said hanger bracket by a cylindrical pin or with compliant rubber bushing. 
     
     
         3 . A suspension of  claim 2  wherein the said middle portion of the said trailing arm is connected to spherical segments below and above the said trailing arm. 
     
     
         4 . A suspension of  claim 3  wherein the said spherical segments are contained in matching spherical cavities or spherical projections in the spherical blocks above and below the said trailing arm. 
     
     
         5 . A suspension of  claim 4  wherein a spherical ball is used between the said spherical segments and the said spherical blocks as an alternative arrangement. 
     
     
         6 . A suspension of  claim 5  wherein bearing bushings interface between the spherical surfaces of said spherical segments and said spherical blocks or said spherical ball. 
     
     
         7 . A suspension of  claim 6  wherein the said spherical blocks are rigidly connected to the axle by U shaped bolts or straight bolts intended to prevent relative movements between the axle housing and the spherical joint assembly formed by the said spherical segments and said spherical blocks. 
     
     
         8 . A suspension of  claim 7  wherein the middle portion of the trailing arm articulates about the center of the said spherical joint formed by the said spherical segments and said spherical blocks. 
     
     
         9 . A suspension of  claim 8  wherein there is provided a bracket rigidly attached to the said axle for connecting one end of the link rod to the axle, opposite to the side of the said spherical joint with regard to the axle axis. 
     
     
         10 . A suspension of  claim 9  wherein said link rod is pivotally connected to the said axle bracket by a cylindrical pin or with compliant rubber bushing for connecting one end of the said link rod to the axle assembly. 
     
     
         11 . A suspension of  claim 10  wherein the other end of the said link rod is pivotally connected by a cylindrical pin or with compliant rubber bushing to the said hanger bracket. 
     
     
         12 . A suspension of  claim 11  wherein the assembly comprising the said trailing arm, said spherical segments, said spherical blocks, said U-shaped bolts, said bracket for connecting the said link rod to the axle, said hanger bracket and said pins are geometrically arranged to form a four bar mechanism. 
     
     
         13 . A suspension of  claim 12  wherein the said spherical joint is formed below or above said axle section. 
     
     
         14 . A suspension of  claim 13  wherein the center of the said spherical joint is below or above or within the thickness of the said trailing arm. 
     
     
         15 . A suspension of  claim 14  wherein an air spring is connected to the said trailing portion of the said trailing arm either directly to the said trailing arm or through an adapter. 
     
     
         16 . A suspension of  claim 15  wherein the other end of the said air spring is connected to the said frame rail of the vehicle. 
     
     
         17 . A suspension of  claim 16  wherein one end of a shock absorber is connected to the suspension assembly and the other end of the shock absorber is connected to the said frame rail either directly or through an adaptor. 
     
     
         18 . The suspension of  claim 17  wherein a pair of said trailing arm assemblies connected to either side of driven axle assembly and connected to the frame rails form a vehicle suspension system wherein the driven axle angle is maintained substantially constant in any vertical position of the said driven axle. 
     
     
         19 . The suspension assembly of  claim 18  wherein the said axle is laterally controlled in its lateral travel by a tie rod spherically or pivotally connecting one of the said frame rail and the said axle.