Vibration isolation apparatus

A vibration isolation apparatus comprising:

• a first member connected to one of a vibration producing portion and a vibration receiving portion and comprising an outer cylinder;
• a second member connected to the other of the vibration producing portion and the vibration receiving portion and comprising an inner cylinder axially penetrating inside said outer cylinder;
• an elastic member provided between said outer and inner cylinders, and deforming when vibration is generated such that said inner cylinder is movable relative to said outer cylinder;
• a main fluid chamber provided adjacent said elastic member and able to expand and contract;
• an auxiliary fluid chamber separated from said main fluid chamber;
• a unit comprising first and second intermediate blocks having a plurality of restricted paths communicating with said main fluid chamber and said auxiliary fluid chamber, and at least one restricting means for restricting a flow of fluid in at least one but not all of said restricted paths, said restricting means comprising a rotary member rotatable about an axis thereof so as to open and close at least one but not all of said restricted paths, said unit being provided inside said outer cylinder and said auxiliary fluid chamber and said main fluid chamber being arranged at different positions on a circumferential surface of said inner cylinder;
• and
• a controlling means for controlling said rotary member depending on a frequency of vibration generated from the vibration producing portion.