Liquid-sealed vibration-proof device

摘要

To eliminate vibrations and noise in higher-order components of explosive vibrations of an engine in its idling revolution range, an insulator and a vibration-absorbing mechanism formed in line with the insulator are provided between an upper coupling member to be mounted on a vibratory body and a lower coupling member to be mounted on the car body. The vibration-absorbing mechanism comprises a main chamber sealed with liquid, a subsidiary chamber connected to the main chamber through a first orifice, an air chamber provided below the subsidiary chamber, a third liquid chamber connected to the main chamber through a second orifice, and a balance chamber partitioned and formed to the third liquid chamber through a second diaphragm. The balance chamber is provided with a changeover means introducing a negative pressure or atmospheric pressure and a control means controlling the actuation of the changeover means so as to synchronize it to vibration frequencies of higher-order components.