Variable stiffness bushing using magnetorheological elastomers

A variable stiffness automotive vehicle suspension bushing (10) comprises a shaft or rod (12) connected to the vehicle subframe, an inner cylinder (14) fixedly connected to the shaft or rod (12), and an outer cylinder (16) fixedly connected to a vehicle suspension control arm. A magnetorheological (MR) elastomer (20), having iron particles embedded therein, is interposed between the inner (14) and outer (16) cylinders, and a coil (24) is disposed about the inner cylinder (14). When the coil (24) is energised by electrical power from the vehicle battery, a variable magnetic field is generated so as to influence the magnetorheological (MR) elastomer (20) whereby variable stiffness and modulus values or, characteristics of the elastomer (20) are derived so as to provide the bushing (10) with variable spring rate or stiffness characteristics in order to, in turn, provide the vehicle with optimal ride characteristics. Energisation of the coil (24) may be controlled by means of a suitable computer mounted upon the vehicle and which is responsive to various vehicle input data, such as, for example, engine speed, vehicle speed, vehicle acceleration, wheel height, and the like.