AIR SPRING

PROBLEM TO BE SOLVED: To provide an air spring applicable as a seismic isolator in a vertical direction to a structure such as a building.SOLUTION: A diaphragm 3 comprising a mortar-like or cylindrical rubber film is disposed inside a gap 4 between an outer cylinder 1 and an inner cylinder 2 to form an air chamber 5; flange-like bead parts 3a and 3b swollen to the outer side and the inner side corresponding to the diameter dimension of the outer cylinder and the inner cylinder are formed respectively at the upper end part and lower end part of the diaphragm; and the respective bead parts are airtightly tightened and fixed respectively to the outer cylinder and the inner cylinder by tightening metal fittings 6a and 6b. A bead part reinforcing member of a bead wire or a metal ring comprising a metal wire of 30% or more of the entire thickness is embedded in the bead parts and an interference there is 20% or more. The gap between the outer cylinder and the inner cylinder is in the range of 3 times or more and less than 10 times of the film thickness of the diaphragm, bias reinforcing fibers are embedded in the peripheral surface of the diaphragm, the internal space of the inner cylinder is communicated with the air chamber through an orifice 9 as an auxiliary tank 8, and the outer cylinder is provided with a stiffening rib 10.