Hydraulically damped rubber cartridge spring

In a hydraulically damped rubber cartridge spring, comprising an external sleeve and an elongate internal tube having a longitudinal central axis, said external sleeve and said internal tube being supported, one on the other, by an elastomeric spring body having two opposing ends, said internal tube being movable laterally with respect to said external sleeve in response to laterally introduced vibrations, said spring body having a plurality of walls defining two liquid-filled pairs of chambers arranged in axial adjacent relationship at the opposing ends of the spring body, with one pair at each end, the chambers of each pair being spaced apart in the direction of said lateral vibrations with at least one wall of each chamber providing a bulging elasticity, the chambers of each pair being connected via a liquid-filled damping opening;

• the improvement wherein each damping opening is dimensioned and adjusted to the sum of the bulging elasticities of the walls of the respective pair of chambers to which it is connected, such that the liquid contained in the chambers is made to resonate when vibrations of a mutually different frequency are introduced.