Compact Self-Damped Pneumatic Isolators for Road Vehicles

Abstract

Better isolation of vibration and minimum resonant transmissibility of a self-damped pneumatic isolator is achieved when the incorporated surge lank possesses a large volume compared to that of the isolator. This implies that the self-damped pneumatic isolator employed in vibration isolation for road vehicles is quite bulky and not practical for isolation systems where space and mass are the main limitations. It is also assumed that the surge tank has a fixed volume which is independent of relative motions of the body and the wheel. These drawbacks have been avoided by introducing a smaller surge tank, in the form of another pneumatic isolator, which is placed between the wheel and the road surface. It is shown that these two pneumatic isolators together with the capillary restrictor provide the damping mechanism in the form of the self-damped pneumatic isolator. Moreover, this variable volume surge tank acts as a sensor for the relative motion of the wheel and, hence, improves the displacement transmissibility of the body considerably. An optimization method is developed to evaluate the optimum values of the variables to yield the minimum transmitted motion to the body.