A vibroisolating device (1) comprises a substantially elastomeric core (2) configured to be connected with a first displaceable object (3) and provide with an opening (21) configured to be connected with a second displaceable object (4). In order to obtain a nonlinear force vs. displacement characteristic of the device, substantially symmetrical around a certain and adjustable nonzero displacement value, the device (1) comprises at least one Belleville spring (5) disposed on the vibration transmitting path between said first displaceable object (3) and said second displaceable object (4), which is at least partially embedded in the volume of said substantially elastomeric core (2) and surrounds said opening (21). In particular the spring (5) is preloaded while said vibroisolating device (1) is in vibrations equilibrium position. The invention also relates to a motor vehicle suspension, in particular an adjustable active suspension system, comprising such a vibroisolating device.