| 摘要 |
PROBLEM TO BE SOLVED: To facilitate flexure of a noncircular elastic membrane in contrast with the difficulty with flexure that an elliptic or other noncircular member, which only replaces an existent circular elastic membrane, has corresponding to a change in the liquid pressure of a main liquid chamber because a long area is sandwiched along long side portions and stopper projections become continuous in a circle. SOLUTION: An elastic membrane 27 has an elliptic form with long side portions 57 and short side portions 58, and a body portion 50 thereof has a flexure groove 51 parallel to the long side portions 57 in the obverse center. A pair of stopper projections 52 holding the flexure groove 51 in between in a parallel relation is integrally protruded from the reverse of the elastic membrane 27. Both longitudinal ends of each stopper projection are a free end, and the shorter side portions have no stopper projections to provide a discontinuous structure. An input of vibration of a small amplitude causes the body portion 50 to bend or shear on the flexure groove 51 to realize a low dynamic spring, and an input of large-amplitude vibration causes the stopper projections to press against a partition member 16 and deform elastically to provide a non-linearly changed dynamic spring constant and thus improved damping. |
