Hydraulic antivibration device with a spacer

A hydraulic antivibration device for interposing between two elements, the device comprising two rigid strength members suitable for fastening respectively to two rigid elements that are to be united, the device including a working chamber and a compensation chamber, a constricted passage putting the two chambers into communication with each, the two chambers and the passage being filled with liquid, the device including a decoupling flap disposed between the two chambers, said flap being movable over a short stroke, at least one perforated rigid partition separating the two chambers, said partition being closed by the flap, the flap being in the form of a plate of elastically deformable material, wherein the flap is disposed in an opening in a spacer clamped between first and second grids, the two grids being plane and parallel and disposed respectively in the working chamber and the compensation chamber, the stroke available for the flap between the grids being defined by the thickness of the spacer, the constricted passage putting the working chamber and the compensation chamber permanently into communication being constituted by a channel made integrally with the spacer.