Fluid-filled engine mount device

Claim 1

An engine mount device comprising: first and second base plate members which are spaced from each other and connected to a power unit side and a vehicle body side, respectively; a block made of elastic material and having a cavity, said block being interposed between and secured to said first and second base plate members; a partition plate member having an orifice, said partition plate member defining a fluid chamber between it and the wall surface of said elastic block cavity; a diaphragm member affixed to said one of said first and second base plate members and defining an auxiliary chamber between it and said partition plate member, said auxiliary chamber being in communication with said fluid chamber though said partition plate member orifice, at least a part of said fluid and auxiliary chambers being filled with a fluid; a rigid ring disposed around the intermediate section of said elastic block restricting the radial expansion of said elastic block; and dynamic damper means including a vibration system constituted by said elastic block and said rigid ring, the natural frequency of said vibration system being so set as to make the resonance vibration of said vibration system have a predetermined frequency, the natural frequency of said vibration system being set at a value expressed by the following equations: ##EQU3## and additionally, 50Hz≦f≦400 Hz where "W" is the weight of said rigid ring; "k" is the spring constant of said elastic block in the axial direction in which said elastic block expands and contracts in response to an input vibration; and "g" is gravitational aceeleration.