Elastic mount having at least two orifices formed by rubber filler on orifice-defining structure which extends along at least one of two fluid chambers

A fluid-filled cylindrical elastic mount comprising:

• an inner and an outer sleeve which are radially spaced apart from each other;
• an elastic body interposed between said inner and outer sleeves, for elastically connecting the inner and outer sleeves, said elastic body having a first and a second pocket formed in respective diametrically opposite circumferential portions thereof, said first and second pockets being open in an outer circumferential surface of said elastic body;
• said first and second pockets cooperating with said outer sleeve to define a first and a second fluid chamber, respectively, said first and second fluid chambers being filled with a non-compressible fluid;
• an orifice-defining structure interposed between said outer sleeve and said elastic body, and extending in a circumferential direction of said outer sleeve, so as to cover at least one of said first and second pockets, said orifice-defining structure having a circumferential recess open in a radially outward direction of said outer sleeve, said orifice-defining structure having a first and a second window formed through said circumferential wall;
• a rubber filler provided in said circumferential recess, and having a first and second groove which extend from said first and second windows, respectively;
• a flexible diaphragm formed integrally with said rubber filler and closing said second window;
• said first groove and said first window cooperating with said outer sleeve to define a first orifice passage for fluid communication between said first and second fluid chambers;
• and
• said second groove cooperating with said outer sleeve to define a second orifice passage which permits said fluid to flow between a region of said second orifice passage adjacent said flexible diaphragm and said second fluid chamber, through elastic displacement of said flexible diaphragm, said second orifice passage having a higher ratio S/L than said first orifice passage, where S and L respectively represent a cross sectional area and a length of said first and second orifice passages.